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 1alpha,25-dihydroxyvitamin D3.
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 1alpha,25-dihydroxyvitamin D3.
Miyata
O
O
Kobe Pharmaceutical University, Higashinada, Japan.
Nakajima
E
E
Naito
T
T
D002117:Calcitriol / Q000138:chemical synthesis* / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D013457:Sulfur Compounds / Q000737:chemistry*
D006571:Heterocyclic Compounds; D013457:Sulfur Compounds; D002117:Calcitriol