The structure and stereochemistry of Edulan I and II and the stereochemistry of the 2,5,5,8a-Tetramethyl-3,4,4a,5,6,7,8,8a-octahydro-2H-1-benzopyrans

Abstract

Edulan I and 11, two important trace components of the juice of passionfruit Passiflora edulis (Sims), were shown by micro-reaction g.l.c., by micro-spectrometry (m.s., N.M.R., i.r. and u.v.) and by com- parison with synthetic products to be the epimeric 2,5,5,8a- tetramethyl-3,5,6,8a-tetrahydro-2H-1-benzopyrans (8a) and (8b). The relative configurations of these isomers were established by their con- version into the stereoisomeric 2,5,5,8a-tetramethyl-3,4,4a,5,6,7,8,8a- octahydro-2H-1-benzopyrans (6a,b) and (6c,d) respectively. The evidence leading to the assignment of the relative stereochemistry to the tetramethyloctahydrobenzopyrans is presented.