Katsuhide Okada

Synthesis of naturally occurring brassinosteroids employing cleavage of 23,34-epoxides as key reactions. Synthesis of brassinolide, castasterone, dolicholide, dolichosterone, homodolicholide, homodolichosterone, 6-deoxocastasterone and 6-deoxodolichosterone☆

Abstract Eight new plant growth-promoting steroids (brassinolide, castasterone, dolicholide, dolichosterone, homodolicholide, homodolichosterone, 6-deoxocastasterone and 6-deoxodolichosterone) were synthesized by the regio- and stereoselective ring-opening reactions of 23,24-epoxides prepared from stigmasterol.

Synthesis of (22S, 23S)-homobrassinolide and brassinolide from stigmasterol

Abstract (22S, 23S)-Homobrassinolide (2α, 3α, 22S, 23S-tetrahydroxy-24S-etyl-B-homo-7-oxa-5α-cholestan-6-one) and brassinolide (2α, 3α 22R, 23R-tetrahydroxy-24S-methyl-B-homo-7-oxa-5α-cholestan-6-one) were synthesized from stigmasterol and shown to promote plant growth.

Synthesis of mevalonolactone (hiochic acid lactone) employing asymmetric epoxidation as the key-step

Abstract (R)( — )-Mevalonolactone (hiochic acid lactone)of 91–93%e.e. was synthesized from an achiral starting material employing the Sharpless asymmetric epoxidation as the key-step.