Addition of a functionalized isoprene unit to an allyl alcohol. Part II. Reactions with furylmethanol and thienylmethanol and synthesis of torreyal and dendrolasin

Abstract

The double bond in the furan and thiophen ring can be induced to participate in a Claisen–Cope-type rearrangement. Furans substituted in the 2-position react more readily than those substituted in the 3-position. The 2-methyl-buta-1,3-dienyl ether of 3-furylmethanol can, however, be made to rearrange thermally, and the aldehyde thereby obtained can be converted into the corresponding alcohol, and then, by a second Claisen–Cope reaction to torreyal. The related sesquiterpenes, neotorreyol and dendrolasin and the monoterpene perillene have been synthesized.