Synthesis of (3aR*,6aR*)-2,2,5,6-Tetramethyl-1,2,3,3a,4,6a-hexahydropentalene: A Potential Precursor of Protoilludane Sesquiterpenes

Synthesis and rearrangement of [1,1′-bicyclobutyl]-1-ols and spiro[3.4]octan-5-ols: a general access to bicyclo[3.3.0]octenes (hexahydropentalenes)

“…While cyclobutanones of greatest structural diversity are readily accessible, 4 Wittig and Grignard reagents based on substituted cyclobutanes are rare. 5,6 Therefore, substituents in that part of a bicyclooctene originating from such a reagent may be difficult to establish.…”