Efficient reduction of organic compounds with sulfurated calcium borohydride [Ca(S3BH2)(2)], a new and stable modified borohydride reagent

摘要

Sulfurated Calcium, magnesium, and berelium borohydrides are prepared by metathetical reaction between NaBH2S3 and Ca, Mg, and Be chlorides in dry THF and the effect of metal cation exchange on their stability and reactivity has been presented. In this study we have shown that Ca(BH2S3)(2) is much more stable and more reactive than its Mg, Be, and Na analogues. Ca(BH2S3)(2) can easily reduce carbonyl compounds such as aldehydes, ketones, acyloins, alpha-diketones, alpha-beta-unsaturated carbonyl compounds, aroyl azides, and carboxylic acid chlorides to their corresponding alcohols in good to excellent yields. Epoxides are also effected by this reagent and produce their symmetrical dihydroxydisulfides in good yields. [References: 23]