Oxalic Acid → (3S,4R)-3-[(1R)-1-(tertbutyldimethylsilyloxy)ethyl]-4-[(1-methylthio-1-propenyl)thio]-2-oxoazetidine

関与物質

反応条件

反応手順

To a suspension of Tin(II) trifluoromethanesulfonate (5.58 g) in dichloromethane (27 ml) cooled to -25° C. were added triethylamine (1.62 g) and methyl dithiopropionate (1.20 g) successively. The mixture was stirred for 2 hours at -20° C. and (3R,4R)-4-acetoxy-3-[(1R)-1-(tertbutyldimethylsilyloxy)ethyl]-2-oxoazetidine (2.0 g) was added thereto. After stirring for 2 hours at 0° C., the mixture was poured into 20% aqueous solution of oxalic acid (100 ml) and the precipitates were filtered off. The organic layer of the filtrate was separated, dried, and concentrated under reduced pressure. The residue was purified by silica gel (50 g) column chromatography (20% ethyl acetate-hexane) to afford (3S,4R)-3-[(1R)-1-(tertbutyldimethylsilyloxy)ethyl]-4-[(1-methylthio-1-propenyl)thio]-2-oxoazetidine (mixture of E and Z isomers) (1.14 g).

情報源と証拠