Recent developments in the synthesis of drimane and lactarane sesquiterpenes

Abstract

Several new methods for the construction of ene-dialdehyde functionalities and for the regioselective annulation of butenolides were developed and applied in the synthesis of drimane and lactarane sesquiterpenes. Optically active drimanes were synthesised starting from S-(+)- and R-(−)-carvone. A new development in this approach starts with a conjugate addition of cyanide to the enone in carvone, followed by an annulation reaction. Base-induced and directed reactions of substituted trans — perhydronaphthalene-1,4-diol monosulfonate esters in apolar solvents provide an effective route to cis -perhydroazulene systems. The rearrangement can be directed towards intramolecular ether formation. Based on this approach a total synthesis of lactaranes is under investigation. © 1994 IUPAC