Search

A total synthesis of 6,7-dihydroeponemycin 2 was achieved via the epoxide intermediate 8a . Unresolved absolute configuration of the epoxide ring in 2 and eponemycin 1 was determined to be 2 R by application of the asymmetric Sharpless epoxidation of 9 .

Controlled crisscross annulation was applied to the synthesis of (±)-dihydrodesoxyotonecine, a degradation product of secopyrrolizidine alkaloids.

The synthesis of the nuclei of pyrrolizidine and indolizidine could be readily achieved by use of the one pot reaction named as “crisscross annulation”, which was extended to the synthesis of (±)-heliotridane ( 16 ) and (±)-nuphar indolizidine ( 20 ), a minor component of dried scent glands of the Canadian beaver.

Phoracantholide I, having a ten-membered lactone, was synthesized through a new synthetic method which includes a cyclic acetylenic oxy-Cope rearrangement and ring-expansion by the Baeyer-Villiger oxidation of a nine-membered ketone.

A synthesis of 9a-hydroxy-5,8-dideoxomitosanes was accomplished by the transannular cyclization of hydro-1-benzazocinone intermediates derived from 3-(2,5-dioxo-1-methylcyclopentyl)-6-methyl-p-phenylenediamine derivatives. These mitosanes were led to the 8-membered ring system by an oxidative ring-opening reaction.

(±)-Tryptoquivaline G was formally synthesized through shortened steps from tryptophan, in which oxidation with thallium(III) trinitrate(TTN) was effected at the crucial stage. The present work also constitutes the first synthesis of oxindole lactones carrying 2-alkyl quinazolinones.