The remote effect of D ring moiety on selectivity between 4-dimethylation and 3-O-methylation on steroidal compounds / 复旦学报（医学版）

ABSTRACT

Objective To introduce dimethyl on 4-position of 4-ene-3-one steroids. Methods Seven 4-ene-3-one steroids were treated with methyl iodide (CH3I) and potassium tert-butoxide (t-BuOK) in tert-butanol (t-BuOH). Results Four substrates were smoothly converted to 4,4-dimethyl products, while other three substrates afforded 3-O-methylation products with high yields. Conclusions The different reaction results revealed a high remote effect of D ring moiety on the selectivity between 3-O-methylation and 4-dimethylation.