Aspects of the Reduction of Double Bond Using Cob(I)alamin as Catalyst

Article abstract of DOI:10.1002/hlca.19820650839

The olefinic system in 3β-methoxy-4-cholesten-6α-ol (2) is reduced using cob(I)alamin (1(I); see Scheme 1) as catalyst; aqueous acetic acid as solvent and metallic zinc as electron source (cf.Schemes 2 and 3).Experimental evidence for an attack of 1(I) on both faces of the double bond is presented.By the same catalyst (1R)-10,10-dimethyl-2-pinene-10-carbonitrile (9) is first transformed to the menthene derivative 11 (see Schemes 4 and 5).The ring opening is then followed by a fast saturation of the disubstituted olefinic system in 11, and ultimately the remaining double bond is reduced in a slow reaction.The cis-configurated saturated menthane derivative 16 is the main final product (16/17 ca. 10:1).