An 8pi electron electrocyclization leading to a 9,19-methano-bridged analogue of 1 alpha,25-dihydroxyvitamin D3.
[reaction: see text] Lindlar semihydrogenation of a vitamin D type trienyne leads spontaneously to 9 alpha,19-methano-1 alpha,25-dihydroxyvitamin D3. The intermediate tetraene resulting from the reduction undergoes a rapid, stereoselective 8pi electron electrocyclization affording a novel steroid containing a linearly fused ABC (six-eight-six) 1,3,5-cyclooctatriene carbon framework.
Hayashi
Rena
R
Department of Chemistry, University of California, Riverside, California 92521, USA.
Fernández
Susana
S
Okamura
William H
WH
D001952:Bridged-Ring Compounds / Q000138:chemical synthesis; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D003500:Cyclization; D004583:Electrons; D013057:Spectrum Analysis
D001952:Bridged-Ring Compounds; D002117:Calcitriol