Benzoquinones and related compounds. Part I. Crystal and molecular structure of 1,4,4a,5,8,8a,9a,10a-octahydro-1,4:5,8-dimethano-9,10-anthraquinone, a Diels–Alder adduct from 1,4-benzoquinone and cyclopentadiene
Abstract
X-Ray crystallography of the Diels–Alder adduct from 1,4-benzoquinone and two equivalents of cyclopentadiene confirms that its stereochemistry is endo,cis,anti,cis,endo. Crystals are monoclinic, space group P21/c, Z= 4, a= 11.992(8), b= 6·236(4), c= 16·977(9)Å, β= 110·63(9)°. The structure was solved from diffractometer data by symbolic addition methods and refined by least-squares techniques to R 6·6 for 1294 independent reflexions.