The structure and stereochemistry of the hexahydroisochromanone from the carvenone–benzaldehyde condensation

Abstract

The product obtained by Wallach from the carvenone–benzaldehyde condensation is shown to be 4a-chloro-4,4,7-trimethyl-1,3-diphenyl 4a,5,6,7,8a-hexahydroisochroman-8-one, by stepwise aromatisation to 8-hydroxy-4,4,7-trimethyl-1,3-diphenylisochroman and subsequent rearrangement to 4-hydroxy-1,1,5-trimethyl-2,3-diphenylindene. The mechanism of dehydrochlorination of this product is elucidated; this, in conjunction with n.m.r. evidence, indicates the stereochemistry of the title compound.