101(P-58) サリシリハラミドAの合成研究(ポスター発表の部)

概要

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Synthesis of Salicylihalamide A (1) was carried out using palladium-catalyzed hydrogenolysis of alkenyloxiranes as key reactions for constructing stereogenic centers of 1. Starting with the allylic alcohol 4, Sharpless asymmetric epoxidation of 4, followed by oxidation of the alcohol to the corresponding aldehyde and Emmons olefination using Ando's reagent gave the optically acitve (Z)-alkenyloxirane 9. The reductive opening reaction of the oxirane was carried out selectively with retension of stereochemistry to give the alcohol 10 in 70% yield. After protection of the alcohol as TBDMS ether, ester was reduced with DIBAH followed by benzoylation to give the allylic ester 11. Hydrogenolysis of 11 with formic acid in the presence of palladium catalyst gave the terminal olefin 12. After deprotecton of PMB ether with DDQ followed by Parikh-Doering Oxidation, Emmons reaction, and subsequent reduction gave the allylic alcohol 13. The acohol 13 was converted to the alkenyloxirane 15 in 3steps, and reductive ring opening of the oxirane with formic acid in the presence of palladium catalyst gave the alcohol 3. Esterification of the alcohol 3 with 5 under Mitsunobu condition gave the ester 17. Ring closing metathesis of 17 was carried out to give 18 in 73% yield. 18 was a useful intermediate for the total synthesis of Salicylihalamide A (1).
2001-09-01