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A Reductive Elimination of Steroidal Diol Monoesters with Zinc Giving the Corresponding Olefins

1977; Oxford University Press; Volume: 50; Issue: 1 Linguagem: Inglês

10.1246/bcsj.50.186

1348-0634

Giichi Goto,

Organic and Inorganic Chemical Reactions

Steroidal cis-diol monoacetates (1,9,11, and 13) were refluxed with zinc powder in acetic acid to give the corresponding olefins (2,10,12, and 14) in good yield. Under the reaction conditions, no reaction occurred with diol diacetates (1b: R1=R2=H, R3=R4=Ac and 1m: R1=C6H5, R2=H, R3=R4=Ac) and trans-diol monoacetates (15 and 16). Acyclic erythro and threo diol monoacetates (17 and 19) underwent highly stereoselective reduction affording 18 and 20, respectively. The olefin-forming elimination proceeded with syn-elimination of a cyclic orthoacetate intermediate (21). The effect of some metals on the reduction and the behavior of a number of esters (26) and orthoesters (27) were also investigated.