Structural studies of organoboron compounds. XXX.' 1,9-Dimethyl-3,5,7-triphenyl-2,4,6,8-tetraoxa-1,9-diazonia-5-bora-3,7-

diboratatri~~clo[5.4.0.0~~ 'lundecane

HENNING AMT AND WOLFGANG KLIEGEL Institut fiir Pharmazeutische Chemie, der Technischen Universitat Braunschweig, BeethovenstraPe 55,

3300 Braunschweig, Bundesrepublik Deutschland

AND

STEVEN J. RETTIG AND JAMES TROTTER Department of Chemistry, Universio of British Columbia, 2036 Main Mall. Vancouver, B.C., Canada V6T I Y6

Received September 17, 1987

HENNING AMT, WOLFGANG KLIEGEL, STEVEN J. RETTIG, and JAMES TROTTER. Can. J. Chem. 66,1117 (1988). Details of the preparation and physical properties of the title compound are given. Crystals of 1,9-dimethyl-3,5,7- triphenyl-

2,4,6,8-tetraoxa-1,9-diazonia-5-bora-3,7-diboratatricyclo[5.4.0.03g]undecane are orthorhombic, a = 9.4026(3), b = 9.4663(2), c = 24.7462(9) A, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.036 and R , = 0.038 for 1536 reflections with1 2 3u(f). The three six-membered and two seven-membered rings comprising the tncyclo[5.4.0.0'* 'Iundecane ring system all have boat or boat-like conformations. Important bond lengths (corrected for libration) are: B(sp3+~ = 1.649(6) and 1.668(6), B ( sp3W(N) = 1.492(5) and 1.497(6), ~(sp~)- -O[~(sp~)] = 1.444(6) and 1.438(5), B(sp3)-C = 1.600(6) and 1.594(7), B(sp2)--0 = 1.357(6) and 1.370(6), B(sp2)-C = 1.574(6) A.

HENNING AMT, WOLFGANG KLIEGEL, STEVEN J. RETTIG et JAMES TROTTER. Can. J. Chem. 66,1117 (1988). On rapporte les details de la preparation et de IadCtermination de la structure du compose mentionnne dans le titre. Les cnstaux

dudimkthyl-1,9 triphknyl-3,5,7 tetraoxa-2,4,6,8 diazonia-1,9 bora-5 diborata-3,7 tri~~c10[5,4,0,0~~~]und~cane sont orthorhom- biques avec a = 9,4026(3), b = 9,4663(2) et c = 24,7462(9) A, z = 4et groupe d'espace P2,2121. On arCsolu la structure pardes methodes directes et on I'a affinke par la mCthode des moindres carrCs (matrice entiitre) jusqu'a des valeurs de R = 0,036 et R , = 0,038 pour 1536 reflexions avec 1 2 3 4 4 . Les trois cycles i six chainons et les deux cycles i sept chainons formant le systtme tr i~~clo[5.4.0.0~. g]undtcane sont tous dans des conformations bateaux ou qui ressemblent a des bateaux. Les longueurs de liaison importantes (corrigkes pour la libration) sont: B ( s p 3 t N = 1,649(6) et 1,668(6), B(sp3)--O(~) = 1,492(5) et 1,497(6), B ( S ~ ~ ) ~ ~ [ B ( ( S ~ ~ ) ] = 1,444(6) et 1,438(5), B(sp3)-C = 1,600(6) et 1,594(7), B ( s p 2 ~ = 1,357(6) et 1,370(6) et B(sp2)-C = 1,574(6) A.

[Traduit par la revue]

Introduction analysis has been carried out in order to provide a definitive

The condensation of N,N1-methylenebis(N-methylhydroxyl- assignment. amine) and phenylboronic acid does not lead to the strained tricyclooctane ring system 1 ("dinoradamantane" skeleton) but gives the bicyclooctane 2 (1) as was confirmed by X-ray crystal structure analysis (2). We have now attempted to synthesize a less strained ring-enlarged homolog of 1 with the tricyclononane structure 4 ("nortwistane" skeleton) by reaction of N,N1- dihydroxy-N,N1-dimethyl-1,2-ethanediamine 3 with phenyl- boronic acid. The crystalline reaction product turned out to be neither a tricyclic (4) nor a bicyclic (5) l:2-condensate of 3 and phenylboronic acid. Quantitative elemental analyses and nmr spectra revealed instead a l:3-condensation product 6. Reaction of 3' and phenylboronic acid in a molar ratio of 1:3 gave 6, expectedly, in better yield. Unfortunately the chemical and spectroscopic data of 6 were not sufficient to decide between possible alternative structures which include the tricyclounde- cane ring system A (known as the "4-homotwistane" skeleton (4)) and the bicycloundecane B which both incorporate a seven- membered ring. The tricycloundecane C and the bicyclounde- cane D, containing eight-membered rings, and the monocyclic undecane ring system E having fluxional N-B coordination are also among the possible structures. An X-ray crystallographic

'Part XXIX: ref. 47. 2~ompound 3 has been synthesized by reduction of the bis(N-

methy1)nitrone of glyoxal(3) with potassium tetrahydroborate.

Experimental N,Nf-dihydroxy-N,N1-dimethyl-1 ,2-ethanediamine 3

A solution of KBH4 (3.2 g, 60 mmol) in 50 mL of water is added dropwise to a solution of N,N1-1 ,2-ethanediylidenebis(methanamine)- N,Nf-dioxide (2.3 g, 20 mmol) (3) in 100 mL of water, warmed to 40°C. The reaction mixture is stirred 24 h at room temperature. Tartaric acid (5 g, 25 mL 20% aqueous solution) is added to the reaction mixture until it is weakly acidic. The reaction mixture is then neutralized (pH 7-8) with NaHC03. The solution is evaporated to dryness and the remaining solid extracted with 4 X 30 mL hot absolute ethanol. Cool- ing down of the collected ethanolic solutions yields 1.3 g (55%) of colorless crystals. Melting point 157°C (from ethanol). Infrared (KBr): 3190 cm-' (@-H). 'H nrnr (d6-DMSOITMS) G(ppm) = 2.5 1 (s, 2 CH3), 2.70 (s, CH2CH2), 7.76 (s, br, 2 OH). Anal. calcd. for C4H12N202: C 39.99, H 10.07, N 23.31; found: C 39.83, H 10.04, N 22.99.

1,9-Dimethyl-3,5,7-triphenyl-2,4,6.8-tetraoxa-1,9-diazonia-5-bora- 3,7-dib0ratatric~clo[5.4.O.d~~~undecane, 6A

3 (0.24 g, 2 mmol) and phenylboronic acid ((a) 0.48 g, 4 mmol, or (b) 0.72 g, 6 mmol) are heated in 50 mL benzene under reflux condi- tions for 1 h using a Dean-Stark trap for continuous water removal. The solution is then evaporated, and the dry residue dissolved in benzene. After addition of petroleum ether and cooling a colorless substance crystallizes. Yields: (a) 0.27 g (42%), (b) 0.65 g (76%). Melting point (decomp.) 201 -203°C (from acetone/ether/petroleum ether). 'H nmr ( d 6 - D ~ S 0 / ~ ~ s ) : G(ppm) = 2.71 (s, 2 CH3), 3.58 and

Can

. J. C

hem

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

129.

12.2

17.2

11 o

n 11

/09/

14Fo

r pe

rson

al u

se o

nly.

1118 CAN. J. CHEM. VOL. 66, 1988

3.78 (m, m, N-CH2CHrN), 7.3-7.4 (m, 9 phenyl-H), 7.8-8.0 (m, 6phenyl-H). Anal. calcd. forC22H25B3N204: C 63.84, H 6.09, B 7.84, N 6.77; found: C 63.35, H 6.09, B 7.92, N 6.81. Crystals suitable for X-ray analysis were obtained by recrystallization from acetone/ether/petroleum ether (2: 1 :drops).

X-ray crystallographic analysis A crystal bounded by the six faces (followed by the distances in mm

betweenparallelfaces): (0 0 1},0.22, (0 1 0},0.32, k(2O 1), 0.40, was mounted in a general orientation. Unit-cell parameters were refined by least-squares on 2 sin 8/X values for 25 reflections (28 = 50-83") measured on a diffractometer with Cu-Ka radiation (X(Kal) =

TABLE 1. Final positional (fractional X lo4) and isotropic thermal parameters (U x lo3 A2)* with estimated standard deviations in

parentheses

Atom x Y z U ~ Q

*U,, = (113) (trace of diagonalized (I).

1.540562, X(Ka2) = 1.544390 A). Crystal data at 22°C are:

Orthorhombic, a = 9.4026(3), b = 9.4663(2), c = 24.7462(9) A, V = 2202.6(1) A3, Z = 4, pc = 1.248 Mg m-3, F(000) = 872, ~(CU-Ka) = 6.33 cm-'. Absent reflections: hOO, h odd, OM), k odd, and 001.1 odd, uniquely indicate the space group P212121 (024, NO. 19).

Intensities were measured with nickel-filtered Cu-Ka radiation on an Emaf-Nonius CAD4-F diffractometer. An 0-28 scan at 1.7-10.0' m i d over a range of (1.10 + 0.14 tan 8) degrees in o (extended by 25% on both sides for background measurement) was employed. Data were measured to 28 = 150". The intensities of three check reflections, measured every 3600 s throughout the data collection, remained con- stant to within 4%. After data red~ct ion ,~ an absorption correction was applied using the Gaussian integration method (5, 6). Transmission factors ranged from 0.809 to 0.878 for 120 integration points. Of the 2588 independent reflections measured, 1536 (59.4%) had intensities

3 ~ h e computer programs used include locally written programs for data processing and locally modified versions of the following: MUL- TAN 80, multisolution program by P. Main, S. J. Fiske, S. E. Hull, L. Lessinger, G. Germain, J. P. Declercq, and M. M. Woolfson; TLS, thermal motion analysis by V. Schomaker and K. N. Trueblood; AGNOST, absorption corrections, by J. A. Ibers; ORFLS, full-matrix least-squares, and ORFFE, function and errors, by W. R. Busing, K. 0. Martin and H. A. Levy; FORDAP, Patterson and Fourier syntheses, by A. Zalkin; ORTEP 11, illustrations, by C. K. Johnson.

Can

. J. C

hem

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

129.

12.2

17.2

11 o

n 11

/09/

14Fo

r pe

rson

al u

se o

nly.

AMT ET AL.

FIG. 1. Stereoscopic view 1,9-dimethyl-3,5,7-triphenyl-2,4,6,8-tetraoxa-1 ,9-diazonia-5-bora-3,7-diboratatricyclo[5.4.0.03~ 9]undecane; 50% probability thermal ellipsoids are shown for the non-hydrogen atoms. Hydrogen atoms have been assigned arbitrary thermal parameters for the sake of clarity.

greater than o r e ual to 3u(l) above background where u2(l) = S + 2B + (O.O4(S - B); with S = scan count and B = normalized background count.

'The structure was solved by direct methods, the coordinates of all non-hydrogen atoms being determined from an E-map. The non- hydrogen atoms were refined with anisotropic thermal parameters and the hydrogen atoms were fixed in idealized ositions (staggered methyls, C(sp2&H = 0.97, C(sp3&~ = 0.98 .f, UH a Ubondld .,,.). Scattering factors for all atoms and anomalous scattering corrections for 0 , N, and C were taken from ref. 7. The weighting scheme w = l /d (F) , where u2(F) is derived from the previously defined u2(l), gave uniform average values of w(lFol - 1 ~ ~ 1 ) ~ over ranges of both IF,I and sin 0 / h and was employed in the final stages of full-matrix refinement of 281 variables. Reflections with I < 3u(l) were not included in the refinement. An isotropic Type I extinction correction (Thomley-Nelmes definition of mosaic anisotropy with a Lorentzian distribution) was applied (8- 10). 'The final value of g was 0.80(9) x lo4. Convergence was reached at R = 0.036 and R, = 0.038 for 1536 reflections with I 2 3 4 4 . For all 2588 reflections R = 0.077. A parallel refinement of the mirror-image structure resulted in R factor ratios of 1.009 on both R andR,v.The function minimized wasCw(l~,I - IF,~)~,R =zll~~l- IFcll/zlFoI and R, = (Cw(lF,(- ~ F ~ I ) ~ / ~ w ~ F , ( ~ ) ' ~ ~ .

On the final cycle of refinement the mean and maximum parameter shifts corresponded to 0.01 and 0.08u, respectively. The mean error in an observation of unit weight was 0.691. The largest peak on the final difference map was 0.16 e k3. The final positional and thermal parameters appear in Tables 1 and 6,4 respectively. Measured and calculated structure factors have been placed in the Depository of Unpublished Data.4 The final F, and F, values for the intense reflections indicate the possibility of anisotropic extinction. The ap- plication of an anisotropic extinction correction in this case, however, was judged inappropriate since only a small number of reflections was involved, and in only one instance was IIFo( - lFcll greater than 3u(F) (3.7uforOO2).

The ellipsoids of thermal motion for the non-hydrogen atoms are shown in Fig. 1. The thermal motion has been analysed in terms of the rigid-body modes of translation, libration, and screw motion (1 1). The rms standard error in the temperature factors aUij (derived from the least-squares analysis) is 0.0031 A2. 'The structural subunits PhB and the tricycloundecane ring system plus the N-methyl carbon atoms were

?he structure factor table, Table 6 (anisotropic thermal parameters) and other material mentioned in the text may be purchased from the Depository of Unpublished Data, CISTI, National Research Council of Canada, Ottawa, Ont., Canada KIA 0S2.

analysed separately (rms AUV = 0.0024-0.0035 A2). The appropriate bond distances have been corrected for libration (1 1, 12). Corrected bond lengths appear in Table 2 along with the uncorrected values. Corrected values for the bond angles and torsion angles for the tricyclo[5.4.0.03. 9]undecane system are within one standard deviation of the uncorrected values given in Tables 3 and 4. Calculated hydrogen coordinates and thermal parameters (Table 5) and a complete listing of torsion angles (Table 7) are included as supplementary material.

Results and discussion The crystal structure of 6 consists of discrete molecules sepa-

rated by normal van der Waals distances. The shortest inter- molecular contacts between non-hydrogen atoms are C(2)...C(5)(1/2 + x, 112 - y, 2 - z) = 3.346(6), C(3)...C(9)(x, y - 1, z) = 3,337(7), andO(1)---C(l)(x - 112, 112 - y, 2 - z) = 3.348(5) A. The structure analysis confirms the existence of the tricyclo[5.4.0.03~ 'lundecane ring system 6A, a heteroana- log of the "4-homotwistane" system (4). The tricycloundecane system contains three six-membered rings and two seven- membered rings which all have boat or boat-like conformations (see Table 4). The conformational flexibility of the eleven- membered ring allows the formation of two transannular N+B coordinative bonds, resulting in formation of the symmetric homotwistane analog. In the related cyclooctane system only one transannular N+B bond is formed to give the fused-ring compound 2 (1, 2), the strained tricyclo[3.3.0.03~7]octane system 1 (Dwdinoradamantane (13)) not existing under normal conditions in the solid state (2). The tricyclic ring system in 6A contains two sp3-hybridized boron atoms with a tetrahedral arrangement of ligands and one sp2-hybridized boron atom. Incorporation of the latter into the ring system is responsible for distortions from an "ideal" homotwistane skeleton, carbocyclic derivatives of which have been synthesized (14). .

Bond lengths5 involving the tetrahedrally coordinated boron atoms in 6A may be compared with those observed for six other compounds having a P ~ B N ( s P ~ ) O ~ ligand set (2, 15-18). While the individual bond lengths involving the boron atoms vary considerably in these "PhBN(sp3)0~ compounds (B--C = 1.582-1.641, 0-B = 1.438-1.497, and N-B = 1.649-

'~ibration corrected bond lengths (esd's assumed equal to those of the uncorrected values) are employed in the discussion and are com- pared with similarly treated (1 1) distances unless otherwise stated.

Can

. J. C

hem

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

129.

12.2

17.2

11 o

n 11

/09/

14Fo

r pe

rson

al u

se o

nly.

CAN. J . CHEM. VOL. 66, 1988

TABLE 2. Bond lengths (A) with estimated standard deviations in parentheses

Length Length

Bond Uncorr. Corr. Bond Uncorr. Corr.

O ( l t N ( 1 ) 1.449(4) 1.452 C(6-(7) 1.389(7) 1.396 O ( l t B ( 1 ) 1.486(5) 1.492 c ( 7 t c ( 8 ) 1.355(9) 1.363 0(2&B(l) 1.439(6) 1.444 c ( S t C ( 9 ) 1.403(9) 1.413 0 ( 2 t B ( 2 ) 1.354(6) 1.357 c(9-( 10) 1.377(7) 1.385 0 ( 3 t B ( 2 ) 1.366(6) 1.370 c ( l l)--C(12) 1.395(6) 1.403 0 ( 3 t B ( 3 ) 1.434(5) 1.438 c(ll)--C(16) 1.391(6) 1.398 0 ( 4 t N ( 2 ) 1.440(4) 1.443 C( l l t B ( 2 ) 1.571(6) 1.574 0 ( 4 t B ( 3 ) 1.49 l(6) 1.497 C(12 tC(13) 1.402(6) 1.405 N( 1)--C(2) 1.481(6) 1.486 C(13 tC(14) 1.373(6) 1.379 N ( l t C ( 3 ) 1.484(6) 1.489 C ( 1 4 ) 4 ( 1 5 ) 1.376(7) 1.384 N(l t B ( 3 ) 1.663 (6) 1.668 C ( 1 5 ) 4 ( 1 6 ) 1.381(6) 1.384 N ( 2 t C ( l ) 1.484(5) 1.488 C ( 1 7 ) 4 ( 1 8 ) 1.389(6) 1.396 W t C ( 4 ) 1.480(5) 1.484 C(17 tC(22) 1.396(7) 1.405 N(ZtB(1) 1 .644(6) 1.649 C ( 1 7 t B ( 3 ) 1.590(7) 1.594 C(l)--C(2) 1.526(7) 1.531 C(18 tC(19) 1.392(7) 1.396 C(s)--C(6) 1.389(6) 1.399 C(19 tC(20) 1.367(8) 1.376 c(s)-C(lo) 1.380(6) 1.388 C(20)-C(2 1) 1.371(7) 1.378 C ( s t B ( 1 ) 1.593(6) 1.600 C(2 1 t C ( 2 2 ) 1.375(6) 1.379

TABLE 3. Bond angles (deg) with estimated standard deviations in parentheses

Bonds Angle (deg) Bonds Angle (deg)

1.759 A), the sums of the bond length! at boron lie within the tems (15), fused-ring systems with the N-B bond at the ring relatively ?mall range of 6.191-6.297 A with an average value junction (2, 16-18), and in the present case a bridged-ring of 6.228 A. These bond length sums are sensitive to ring-size system in which both the B and N atoms occupy briGgehead and other steric effects and are a good indicator of the overall positions. The average bond length sum in 6A, 6.191 A, is the strain at the boron atom and its substituents. These compounds smallest yet observed for a " P ~ B N ( s ~ ~ ) O ~ " compound and is include monocyclic six-membered boron-containing ring sys- indicative of a relatively low-strain system. The staggered con-

Can

. J. C

hem

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

129.

12.2

17.2

11 o

n 11

/09/

14Fo

r pe

rson

al u

se o

nly.

AMT ET AL. 1121

TABLE 4. Torsion angles (deg) for the tricycloundecane sys- tem with estimated standard deviations in parentheses

Atoms Value (deg)

formations about the N-B bonds in 6A are partially responsible for this. In related systems with fully substituted B and N atoms, steric factors result in less favorable conformations about rather long N-B bonds (2, 15, 16).

The average N-B distance of 1.659 A in 6A is the shortest observed for a " P h B ~ ( s p ~ ) $ l ~ " compound; similar to the values of 1.634 (uncorr.)- 1.657 A observed for relatively strain-free N,O-chelates of the type C ( S ~ ~ ) ~ B N ( S ~ ~ ) O (19-24). The bond distances between the tetrahedral boron atoms and the-nitrogen- bound oxygen atoms (mean B---O(N) = 1.495(4) A) are the longest &B distances yet observed for a " P h B ~ ( s p ~ ) 0 ~ " compound but are strikingly short compared with corresponding distances of 1.5 17 (uncorr.)- 1.604 A reported for other boron chelates with N-oxide ligands (25-31). The mean ~ ( s p ~ ) X distance of 1.597(4) A in 6A is close to the uncorrected mean value of 1.602 A observed for the other "PhBN(sp3)02" com- pounds (2, 15- 18).

The two B(sp2)---0 bonds (1.357(6) and 1.370(6) A) are relatively short, demonstrating the partial n-bond character resulting from pp(n) back-donation from the two oxygen atoms to boron within the trigonal planar phenylboronate system. Similar ~ ( s p ' ) - O distances have been reported for the free arylboronic acids PhB(OH)2 (32), mean 1.371(6) A, and 4- B I C ~ H ~ B ( O H ) ~ (33), uncorrected mean 1.36 A. The uncor- rected B(sp2)-4 distanc~s in various phenylboronate de!iva- tives range 1.3 1 1 - 1.42 1 A with an average value of 1.370 A (2, 15, 16, 18,28,30,32-42). The B(sp2)&B(sp3) linkages in 6A are unique among organoboron compounds in that the B(sp2)-0 distances are normal. This may be ascribed to the fact that both oxygen atoms of the phenylboronate moiety are bonded to ~ ( s p ~ ) atoms. In all other structurally characterized

organoboron compounds containing B(sp2)--0-~(sp~) units only one such unit is present, displaying very short B(sp2)--0 bonds (1.31 1- 1.367, uncorrected mean 1.338 A) and normal ~ ( s p ~ ) - O distances (1.444- 1.495, uncorrected mean 1.47 1 A) (2, 15, 16, 18,28,40,42). In the present case it is the ~ ( s p ~ ~ ) - 0[B(sp2)] bonds which are short at 1.436((5) and 1.444(6) A.

The B ( s p 2 w distance of 1.574(6) A i~~slightly longer than the average uncorrected value of 1.552 A , but in the range 1.506- 1.582 A observed for other phenylboronate derivatives (2, 15, 16, 18, 28, 30, 32-42). As expected, the ~ ( s p ' ) X bond is shorter than the ~ ( s p ~ ) X bonds, indicating a n- interaction between the phenyl ring and the trigonal planar boron atom. The sp2-hybridized boron atom is displaced 0.026(5) A from the plane of its substituents and the angle between the normals to the B(2) coordination plane and the associated phenyl mean plane is 7.3", a typical value for such systems.

It can be concluded that in the case of N-methyl and B-phenyl substitution the formation of 6A is favored in the condensation reaction of 3 with phenylboronic acid, even at an adduct ratio of 1:2. 6A appears to be the thermodynamically most stable struc- ture in this complex-building system. The structure of 6A can also be interpreted in terms of the boat form of the well-known (43-46) BONBON ring, conformationally locked by the ethylene bridge between the nitrogen atoms, and containing an additional boronate bridge linking the ring boron atoms (see formula 7).

7 tricycl0[5.4.0.0~~~]undecane system containing

the BONBON boat partial structure

Acknowledgments We thank the Natural Sciences and Engineering Research

Council of Canada and the Fonds der Chemischen Industrie, Frankfurt am Main, for financial support, and the University of British Columbia Computing Centre for assistance.

1. W. KLIEGEL. J . Organomet. Chem. 253,9 (1983). 2. W. KLIEGEL, S. J . RETTIG, and J. TROTTER. Can. J . Chem. 62,

515 (1984). 3. G. ZINNER, 0 . HANTELMANN, and U. DYBOWSKI. Chemiker-

Zeitg. 97,205 (1973). 4. E. OSAWA, K. AIGAMI, N. TAKAISHI, Y . INAMOTO, Y. FUJIKURA,

Z. MAJERSKI, P. VON R. SCHLEYER, E. M. ENGLER, and M. FARCASIU. J. Am. Chem. Soc. 99,5361 (1977).

5. P. COPPENS, L. LEISEROWTZ, and D. RABINOVICH. Acta Crystal- logr. 18, 1035 (1965).

6. W. R. BUSING and H. A. LEVY. Acta Crystallogr. 22,457 (1967). 7. International tables for X-ray crystallography. Vol. IV. Kynoch

Press, Birmingham. 1974. pp. 99- 102 and 149. 8. P. J . BECKER and P. COPPENS. Acta Crystallogr. Sect. A, 30, 129

(1974);30, 148 (1974); 31,417 (1975).

Can

. J. C

hem

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

129.

12.2

17.2

11 o

n 11

/09/

14Fo

r pe

rson

al u

se o

nly.

1122 CAN. 1. CHEM. VOL. 66, 1988

9. P. COPPENS and W. C. HAMILTON. Acta Crystallogr. Sect. A, 26, 71 (1970).

10. F. R. THORNLEY and R. J. NELMES. Acta Crystallogr. Sect. A, 30,748 (1974).

11. V. SCHOMAKER and K. N. TRUEBLOOD. Acta Crystallogr. Sect. B, 24,63 (1968).

12. D. W. J. CRUICKSHANK. Acta Crystallogr. 9 ,747 (1956); 9, 754 (1956); 14, 896 (1961).

13. M. NAKAZAI, K. NAEMURA, H. HARADA, and H. NARUTAKI. J. Org. Chem. 47,3470 (1982).

14. G. FRATER. Helv. Chim. Acta, 62, 1893 (1979). 15. M. YALPANI andR. BOESE. Chem. Ber. 116,3347 (1983). 16. W. KLIEGEL, D. NANNINGA, S. J. RETTIG, and J. TROTTER. Can.

J. Chem. 62,845 (1984). 17. S. J. RETTIG and J. TROTTER. Can. J. Chem. 53, 1393 (1975). 18. S. J . RETTIG, J. TROTTER, W. KLIEGEL, and H. BECKER. Can. J.

Chem. 54,3142 (1976). 19. S. J. RETTIG and J. TROTTER. Can. J. Chem. 51, 1288 (1973). 20. S. J. RETTIG and J. TROTTER. Acta Crystallogr. Sect. B. 30,2139

(1974). 21. S. J. RETTIG and J. TROTTER. Can. J. Chem. 54,3130 (1976). 22. I. CYNKIER and H. HOPE. Acta Crystallogr. Sect. B, 34, 2990

(1978). 23. I. CYNKIER. Cryst. Struct. Commun. 10,797 (1981). 24. R. ALLMANN, E. HOHAUS, and S. OLUNIK. Z. Naturforsch. Teil

B, 37, 1450 (1982). 25. S. J. RETTIG, J. TROTTER, and W. KLIEGEL. Can. J. Chem. 52,

2531 (1974). 26. J. C. JANSEN, M. VERHAGE, and H. VAN KONINGSVELD. Cryst.

Struct. Commun. 11, 305 (1982). 27. W. KLIEGEL, D. NANNINGA, S. J. RETTIG, and J. TROTTER. Can.

J. Chem. 61,2493 (1983). 28. W. KLIEGEL, H.-W. MOTZKUS, S. J. RETTIG, and J. TROTTER.

Can. J. Chem. 62, 838 (1984). 29. W. MARINGGELE, G. M. SHELDRICK, A. MELLER, and M.

NOLTMEYER. Chem. Ber. 117,2112 (1984).

30. W. KLIEGEL, L. PREU, S. J. RETTIG, and J. TROTTER. Can. J. Chem. 63,509 (1985).

31. W. KLIEGEL, S. J. RETTIG, and J. TROTTER. Unpublishedresults. 32. S. J. RETTIG and J. TROTTER. Can. J. Chem. 55,3071 (1977). 33. Z. V. ZVONKOVA and V. P. GLUSKOVA. Kristallografiya, 3, 559

(1958). 34. H. SHIMANOUCHI, N. SAITO, and Y. SASADA. Bull. Chem. Soc.

Jpn. 42, 1239 (1969). 35. A. H.-J. WANG, I. C. PAUL, K. L. RINEHART, JR., and F. J.

ANTOSZ. J. Am. Chem. Soc. 93,6275 (1971). 36. F. ZETTLER, H. D. HAUSEN, and H. HESS. ActaCrystallogr. Sect.

B, 30, 1876 (1974). 37. P. J. Cox, P. D. CRADWCK, and G. A. SIM. J. Chem. Soc. Perkin

Trans. 11, 110 (1976). 38. A. GUFTA, A. KIRFEL, G. WILL, and G. WULFF. Acta Crystal-

logr. Sect. B, 33,637 (1977). 39. M. YALPANI, R. BOESE, and D. BLASER. Chem. Ber. 116, 3338

(1983). 40. W. KLIEGEL, D. NANNINGA, S. J. RETTIG, and J. TROTTER. Can.

J. Chem. 61,2329 (1983). 41. M. J. BROADHURST, C. H. HASSALL, and G. J. THOMAS. Tet-

rahedron, 40,4649 (1984). 42. W. KLIEGEL, H.-W. MOTZKUS, S. J. RETTIG, and J. TROTTER.

Can. J. Chem. 64,507 (1986). 43. L. P. KUHN and M. INATOME. J. Am. Chem. Soc. 85, 1206

(1963). 44. H. J. ROTH and B. MILLAR. Arch. Pharm. Ber. Dt. P h m . Ges.

297,744 (1964). 45. A. SINGH, V. D. GUFTA, G. SRIVASTAVA, andR. C. MEHROTRA.

J. Organomet. Chem. 64, 145 (1974). 46. S. J. RETTIG and J. TROTTER. Can. J. Chem. 61,206 (1983). 47. W. KLIEGEL, S. J. RETTIG, and J. TROTTER. Can. J. Chem. 66,

1091 (1988).

Can

. J. C

hem

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

129.

12.2

17.2

11 o

n 11

/09/

14Fo

r pe

rson

al u

se o

nly.