Reaction of thioketones with carbonyl oxides and 3,3-dimethyl-1,2-dioxirane. [3 + 2] Cycloaddition vs. oxygen atom transfer

Abstract

The ozonolysis of vinyl ethers 1a, b in the presence of adamantane-2-thione 4a and bicyclo[3.3.1]nonan-9-thione 4b gave in each case the corresponding thioozonides 5a–c in moderate yields, whilst ozonolysis of a mixture of vinyl ethers 1a–d and thiobenzophenone derivatives 4f–h gave the corresponding thione S-oxides 8f–h in isolated yields of 10–40%, together with the benzophenones 7f–h. 3,3-Dimethyl-1,2-dioxirane, generated in situ from the reáction of acetone and ‘oxone’(2KHSO₅- KHSO₄-K₂SO₄), transferred an oxygen atom to compounds 4a, f, g, i providing the thione S-oxides 8a, f, g, i in 29–97% yield.