ALLYLIC TERPENYL SILANES, VERSATILE SYNTHONS IN THE TERPENE SERIES - SYNTHESIS OF 2-ACYL-DELTA(1,7)-PARA-MENTHENES AND 3-ACYL-BETA-PINENES

When reacted with acyl chlorides in the presence of aluminium trichloride, 7-(trimethylsilyl)-A(1, 2)-p-menthene underwent substitution of the trimethylsilyl group and allylic rearrangement. Thus, acetyl, isovaleroyl, and senecioyl chlorides yielded their corresponding 2-acyl-Δ(1, 7)-p-menthenes. Similarly, 7-(trimethylsilyl)-β-pinene (resulting from an ene reaction of α- or β-pinene with PhS02NS0 followed by reductive silylation) reacted with acetyl and senecioyl chlorides to give the corresponding 2-acyl-β-pinenes. This route proves to be a highly convenient procedure for the synthesis of this series of allyl ketones having the carbon-carbon double bond in the exocyclic position. © 1979, American Chemical Society. All rights reserved.