1468 J. Am. Chem. SOC. 1991, 113, 1468-1470 biradical but a singlc zwittcrion was in good accord with the chcmical reactivities described above. Further investigations of the ncw intermediate sila-m-quinomethane are in progress. Acknowledgment. Wc arc gratcful for the financial support of thc Ministry of Education, Science. and Culture of Japan (Specially Promoted Research No. 02 102004). (9) Rule, M.; Matlin. A. R.; Hilinsky. E. F.; Dougherty, D. A.; Rerson. J. A. J. Am. Chem. Soc. 1979. 101. 5098. Configuration, Conformation, and Colligative Properties of a Phosphorus-Stabilized Anion Scott E. Denmark,* Paula C. Miller, and Scott R. Wilson' Roger Adams Laboratory, Department of Chemistry C'riirersit)* of Illinois, Urbana, Illinois 6 I80 I Received October 17. I990 As part of a general program to develop chiral, phosphorus- based anionic reagents,' we required an accurate model of the structure and bonding in thcsc species to guide the design of auxiliarics.2 Apart from the pioneering spectroscopic studies on Horner-Wittig reagents by Kirilov3 and Se~den-Penne,~"' the structure of phosphorus-stabilized anions (excluding ylides) has becn 1 it t le investigated .4d-h.5 de Li+i a-: A = H; B = m Li+l b-: A = B = CH3 Wc havc rcccntly rcportcd thc first X-ray crystal structure determinationbR of a phosphoryl-stabilized anion, Li+la-, which 'Correspondence author for inquiries concerning the X-ray structure de- termination. (I) (a) Corey, E. J.; Cane. D. E. J. Org. Chem. 1969.34.3053. (b) Evans, D. A.; Takacs. J. M.; Hurst. K. M. J. Am. Chem. Soc. 1979. 101. 371. (c) Hanessian. S.; Delorme. D.; Reaudoin, S.; Leblanc, Y. J. Am. Chem. Soc. 1984. 106. 5754. (d) Ahlbrecht. H.; Farnung. W. Chem. Ber. 1984. 117. I. (e) Hanessian. S.; Delorme. D.; Beaudoin. S.; Leblanc, Y. Chem. Scr. 1985, 25, NS5. (0 Hua, D. H.; Chan-Yu-King, R.; McKie, J. A.; Myer. L. J. Am. Chem. Soc. 1W7. 109, 5026. (g) Bartlett. P. A.; McLaren. K. L. Phosphorus SuIJtrr 1987.33. 1. (h) Schiillkopf. U.; Schiitte. R. Liebigs Ann. Chem. 1987. 45 and references to earlier work. (i) Togni. A.; Pastor, A. Tetrahedron Irtr. 1989. 30. 1071. (j) Sawamura. M.; Ito. Y.; Hayashi. T. Tetrahedron Left. 1989.30.2247. (k) Haynes. R. K.; Vonwiller. S. C.; Hambley, T. W. J. Org. C'herrr. 1989. 54. 5162 and references to earlier work. (I) Hancssian, S.; Bennani, Y. L.; Delorme. D. Tetrahedron Letr. 1990. 31. 6461. (m) Hancssian. S.; Rcnnani. Y. L. Tetrahedron Lett. 1990. 31, 6465. (2) (a) Dcnmark.S. E.; Marlin. J. E.J. Org. Chem. 1987.52. 5742. (b) Denmark, S. E.; Rajendra. G.; Marlin. J. E. Tetrahedron ktt. 1989.30.2469. (c) Denmark. S. E.; Dorow. R. L. J. Org. Chem. 1990, 55, 5926. (3) (a) Kirilov. 34.; Pctrov, G. Chem. Ber. 1971, 104, 3073. (b) Kirilov, M.; Pctrov. G. Monarsh. Chem. 1972. 103, 1651. (4) Rcvicws: (a) Scyden-Penne. J. Bull. Soc. Chim. Fr. 1987. 238. (b) Str7alko. T.; Scydcn-Pcnne. J.; Froment, F.; Corset, J.; Simonnin, M.-P. J. Chent. Soc.. Perkin Trans. 2 1987.783. (c) Strzalko. T.; Seyden-Penne, J.; Fromcnt. F.; Corsct. J.; Simonnin, M.-P. Can. J. ('hem. 1988, 66, 391. (d) Teuladc. M.-P.; Savignac. P.; About-Jaudet. E.; Collignon. U. Phosphorus SuIJur 1988. 40. 105. See also: (e) Corsct. J. Pure Appl. Chem. 1986, 58, 11 33. (0 Patios. C.; Ricard, L.; Savignac. P. J. Chem. Soc.. Perkin Trans. I 1990. 1577. (g) Yuan. C.; Yao. J.; Li. S.; Mo, Y.; Zhong. X. Phosphorus SuIJur 1989.46. 25. (h) Yao. C. Y. J.; Li, S. Ph0.rphoru.r Sulfur 1990.53. 21. (5) For a rcvicw on the structure of sulfur-stabilized anions: Boche, G. Angew. Chent.. Int. Ed. EngI. 1989. 28. 277. (6) Dcnmark. S. E.; Dorow, R. L. J. Am. Chem. Soc. 1990. 112, 864. 0002-7863/9 1 / I5 13-1 468$02.50/0 ? Figure 1. Crystal structure of [Li+lb-J2.4THFat -75 OC; monomer unit shown for clarity (35% thermal ellipsoids). THF THF b ; *' * #' 8' I , i THF d 80 73 60 50 40 50 20 10 0 PPU Figure 2. I3C NMR spectra (125.8 MHz) at -100 OC. Spectrum A: lb (ncutral. nilturill abundance). Spectrum R: Li+lh- (anion, 50% I3C- cnrichcd in onc C-methyl group). Table I. Planarity Criteria for C(6) (Mean value^)^ anion A R la1 + IBI. deg 1. deg 7, deg d. A Li+la- H Ph 171.1 (35) 359.4 (60) 7.3 0.06 Li+lb- CH3 CH, 165.4 (9) 358.5 (7) 11.6 0.1 1 "The sum of the torsion angles (la1 + 1/31); the sum of all angles about C(6) (E); the angle of the C(6)-P( 1) vector to the C(6)-h-B plane (7); the distance of C(6) to the A-P( I)-B plane (d). established, inter alia, the planarity and preferred conformation of thc carbanionic carbon. In this report we disclose crystallo- graphic and NMR analyses of the related P-isopropyl anion LPlb- (7) Two other types of phosphorus-stabilized anions have been cr stallo- graphically defined: chelated Vg2+ and Cu2+ keto phosphonatesiSb and 1ithiophosphinomethides.'- (a) Weiss. E.; Kopf, J.; Gardein, T.; Corbelin, S.; Schumann. U.; Kirilov. M.; Petrov, G. Chem. Rer. 1985, 118, 3529. (b) Vacicek. J.; Angelova, 0.; Petrov. G.; Kirilov. M. Acra C'rysrallogr. 1988, C44.626. (c) Ryrne, L. T.; Engelhardt, L. M.; Jacobsen. G. E.; Leung, W.-P.; Papasergio, R. I.; Raston, C. L.; Skelton, €3. W.; Twiss, P.; White. A. H. J. Chem. Soc., Dalton Trans. 1989, 105. (d) Karsch, H. H.; Zellner, K.; Mi- kulcik. P.; Lachmann, J.; Miillcr, G. Organomerallics 1990, 9, 190 and ref- erences cited. (e) Fraenkel, G.; Winchester. W. R.; Willard, P. G. Organo- metallics 1989, 8. 2308. (8) The X-ray structure of a diethyl lithiobenzylphosphonate-DABCO complex has recently been reported. Zarges, W.; Marsch, M.; Harms, K.; Hallcr. F.; Frenking, G.; Roche. G. Chem. Ber. 1991, /24(4). We thank Professor Roche for a preprint of this manuscript. 0 1991 American Chemical Society