A new biomimetic-like aromatization of the cyclic end groups of terpenoids with stereospecific migration of one of the methyl groups: a convenient route to isorenieratene (.vphi.,.vphi.-carotene)

Abstract : The synthesis of isorenieratene, a natural carotenoid isolated from the marine sponge Reniera japonica and from some anoxygenic phototrophic bacteria or nonphotosynthetic actinomycetes, was performed from α-, β- and retro-ionones. In this series of cyclohexenes, this synthesis is the first to include a one-pot aromatization of the cyclic end group with concomitant regioselective migration of one Me group from the gem di-Me functionality. [on SciFinder(R)]