Stereospecific construction of multiple contiguous quaternary carbons. Total synthesis of (±)-cis, anti, cis-1,8,12,12-tetramethyl-4- oxatricyclo[6.4.0.02,6]dodecan-3-ol, a thapsane isolated from Thapsia villosa var minor

Article abstract of DOI:10.1021/jo00079a020

The details of the first total synthesis of a natural thapsane 1g containing three contiguous quaternary carbon atoms, starting from cyclogeraniol (9) is described. The Claisen rearrangement of 9 with methoxypropene in the presence of a catalytic amount o