Structure of the 2 + 2 + 2 cycloadduct of bicyclo2.2.1hepta-2,5-diene with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone
Abstract
<h2>Acta Crystallographica Section C</h2><h3>Crystal Structure Communications</h3><h3>0108-2701</h3> <h2>research papers (organic compounds)</h2> Volume 44 Part 11 Pages 1926-1928 November 1988 <h2>Structure of the [2 + 2 + 2] cycloadduct of bicyclo[2.2.1]hepta-2,5-diene with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone</h2> G. I. Fray and J. M. White Acta Cryst. (1988). C44, 1926-1928 Structure of the [2 + 2 + 2] Cyeloadduet of Bieyelo[2.2.1]hepta-2,5-diene with 2,3-Diehloro-5,6-dieyano- 1,4-benzoquinone BY GORDON I. FRAY* AND JONATHAN M. WHITE School of Chemistry, The University, Bristol BS8 1TS, England (Received 7 April 1988; accepted 13 June 1988) Abstract. 11,12-Dichloro- 10,13-dioxopentacyclo- [ 7.4.0.02:.03.5.04.8]tridec- 11-ene- 1,9-dicarbonitrile, C ~s- HsC12N202, Mr=319.15, orthorhombic, P2,2~2 a = 7.741 (2), b= 11.794 (4), c= 14.434 (6)/~, ~1~'= 1317.79 (75):~3, Z=4, Dx= 1.61 gcm-3, 2(Mo K~t) = 0.71073/~, # = 4.96 cm-~, F(000) = 647.91, T=295K, R=0.036 for 1243 unique observed reflections. In the formation of this [2 + 2 + 2] cycload- * To whom correspondence should be addressed. 0108-2701/88/111926-03503.00 duct either the cyclohexenedione ring or the cyano groups could adopt endo stereochemistry; the X-ray study showed that the former is preferred. Introduction. 2,3-Dichloro-5,6-dicyano- 1,4-benzo- quinone (I) is a highly reactive site- and stereo- selective dienophile (Pointer, Wilford & Hodder, 1971; Brown, Bruce, Hudson & Mills, 1974; D/irr, Ruge