2 立体配座解析に基づく中員環歪み分子の合成設計 : ネオカルチノスタチン・エスペラミシン骨格の合成研究(口頭発表の部)  [in Japanese] 2 Synthetic Designing for the Strained Medium Membered Ring Compounds based on Conformational Analyses : Synthetic Studies for Neocarzinostatin and Esperamicin Skeletons  [in Japanese]

The biological activities of Neocarzinostatin and Esperamicin; antitumer biotics, are induced by DNA scission via a proposed mechanism that involves the hydrogen absorption from the phosphate backbone of DNA by the diradicals 3 and 6 produced from the strained intermediates 2 and 5 respectively. Now we synthesized the highly strained 9-membered intermediate 7 using transannular (2,3)-Wittig rearrangement of 12-membered allyl propargyl ether 10, which was obtained by the intramolecular O-alkylation of bromohydrin 11. NCS skeleton 8 was introduced by the dehydration of tertiary alcohol of 7, and Esperamicin model 9 was obtained by the dehydration of secondary alcohol of 7. The diyne 9 led spontaneous Bergman cyclization providing 18.