Unusual Pummerer reactions of 3,4-dihydro-3-hydroxymethyl-6-methoxycarbonyl-1,4-2H-thiazine 1-oxides
Abstract
(3S)-3,4-Dihydro-3-hydroxymethyl-6-methoxy-carbonyl-2,2-dimethyl-1,4-2H-thiazine 1-oxides (2) are converted into (1R,5S)-8-acetyl-2-chloro-2-methoxy-carbonyl-4,4-dimethyl-7-oxa-3-thia-8-azabicyclo[3,2,1]-octane (9) by acetyl chloride in acetonitrile; (3R)-3,4-dihydro-3-hydroxymethyl-6-methoxycarbonyl-1,4-2H-thiazine 1-oxide (3) undergoes an analogous reaction to give (13).