2,2-Dibutyl-1,3,2-dioxastannolens

Acyloins or their enediol carbonates (vinylene carbonates) react with dibutyltin oxide or dibutyltin dimethoxide to give 2,2-dibutyl-1,3,2-dioxastannolens [e.g.(A)].[graphic omitted] 119 Sn N.m.r. and 119mSn Mössbauer spectra, and molecular weight measurements suggest that, in the solid state or in concentrated solution, the dioxastannolen (A) is associated, but the monomer is present in dilute solution.On heating, (A) decomposes into benzil and products which appear to be derived from dibutylstannylene, and it reacts with oxygen to give benzil and products derived from dibutyltin oxide. Acetyl chloride reacts to give cis-stilbene diacetate, but less reactive acylating agents (e.g. acetic anhydride or benzoyl chloride) give an increasing amount of the trans-diester and cyclic anhydrides (e.g. phthalic anhydride), and diacid chlorides (e.g. phosgene) give cyclic esters.