Radical Cyclization in Heterocycle Synthesis. 12. Sulfanyl Radical Addition-Addition-Cyclization (SRAAC) of Unbranched Diynes and Its Application to the Synthesis of A-Ring Fragment of 1.ALPHA.,25-Dihydroxyvitamin D3.
Radical Cyclization in Heterocycle Synthesis. 12. Sulfanyl Radical Addition-Addition-Cyclization (SRAAC) of Unbranched Diynes and Its Application to the Synthesis of A-Ring Fragment of 1.ALPHA.,25-Dihydroxyvitamin D3.
作者:Okiko MIYATA、Emi NAKAJIMA、Takeaki NAITO
DOI:10.1248/cpb.49.213
日期:——
Sulfanyl radical addition-addition-cyclization (SRAAC) of unbranched diynes proceeded smoothly to give cyclized exo-olefins, while the sulfanyl radical addition-cyclization-addition (SRACA) of diynes having a quaternary carbon gave cyclized endo-olefins. This method was successfully applied to the synthesis of A-ring fragment of 1α, 25-dihydroxyvitamin D3.