Asymmetric Synthesis of Vitamin D3 Analogues: Organocatalytic Desymmetrization Approach toward the A-Ring Precursor of Calcifediol.
A novel asymmetric synthesis has been developed for the construction of the A-ring of a chiral precursor to calcifediol. The highlights of this synthesis include (i) the introduction of the stereochemistry at the C5-position of the A-ring through the organocatalytic enantioselective desymmetrization of a prochiral cyclic anhydride using a bifunctional urea catalyst and (ii) the introduction of the exo-cyclic (Z)-dienol side chain by a tandem Claisen rearrangement/sulfoxide thermolysis of an allylic alcohol.
Department of Chemistry, Fudan University , Shanghai 200433, P. R. China.
Haifeng
H
Wang
Department of Chemistry, Fudan University , Shanghai 200433, P. R. China.
Linjie
L
Yan
Department of Chemistry, Fudan University , Shanghai 200433, P. R. China.
Yan
Y
Wu
Department of Chemistry, Fudan University , Shanghai 200433, P. R. China.
Yipei
Y
Lu
Department of Chemistry, Fudan University , Shanghai 200433, P. R. China.
Fener
F
Chen
D000812:Anhydrides; D002112:Calcifediol / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D002762:Cholecalciferol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D020005:Propanols; D013237:Stereoisomerism; D014508:Urea
D000812:Anhydrides; D020005:Propanols; D002762:Cholecalciferol; C006463:allyl alcohol; D014508:Urea; D002112:Calcifediol