Methyl iodide → HCID 67927796, compound

Participants

Reaction Steps

A multistep synthesis of (3R,4R)-3-[1(R)-(t-butyldimethylsiloxy)ethyl]-4-methylsulfonylazetidin-2-one (formula III, X=SO2CH3) from methyl (3S,5R,6S)-6-bromo-6[1(R)-hydroxyethyl]penicillanate is reported by Hirai et al., Tetrahedron Lett. 23, 4021 (1982). The synthesis involves tin hydride debromination of the starting material followed by protection of the hydroxy group of the 6-substituent by silylation with t-butyldimethylsilyl chloride and oxidation of the resulting product to the cis sulfone derivative. The crucial step of the synthesis, reported to be isomerization of the cis sulfone to the trans sulfone, was "satisfactorily" achieved by means of a catalytic amount of 1,5-diazabicyclo [4.3.0]non-5-ene (DBN) in methylene chloride at room temperature. Ring opening of the trans sulfone by treatment with excess methyl iodide and potassium t-butoxide afforded 3-[1(R)-(t-butyldimethylsiloxy)-ethyl]-4-methylsulfonylazetidin-2-one.

Provenance & Evidence