Multiple <i>Wagner‐Meerwein</i> Shift. Biogenesis‐like conversion of (±)‐Δ^7,8‐Protoilludene to (±)‐Hirsutene and related reactions

Abstract

Abstract Experimental details are given for the previous preliminary reports concerning conversion of protoilludane ( 28 ) to hirsutene ( 3 ) and related reactions. Treatment of each of the bicyclic analogs 9 , 10 , 12 and 13 of the former compound afforded a hirsutene analog 8 , through multiple 1,2‐shift, together with other products. Treatment of a mixture of α‐ and β‐protoilludene ‐epoxides ( 29α and 29β ) with BF 3 · Et 2 O in hexane yielded hirsutane derivatives 30 and 32 . Compound 30 in turn was converted to endo ‐hirsutene 36 , which had already been isomerized to hirsutene ( 3 ).