Ethyl chloroformate → Allyl chloroformate

Participants

Reaction Steps

In Scheme 2, 2-bromobenzenesulfonyl chloride (25) and 2-phenyl allyl amine (33) are reacted in the presence of pyridine to generate intermediate (34) which, upon treatment with TBTH and AIBN in toluene gives the radical derived adduct (35) which, when reacted with (2S,3S)-1,2-epoxy-3-(boc-amino)-4-phenylbutane (29) in the presence of Cs2CO3 gives compound (36), as mixture of two diastereomers. The mixture of two diastereomers is treated with TFA:DCM (1:1) to produce compound (37) as a mixture of diastereomers. Treatment of (37) with substituted chloroformates for example ethyl chloroformate in the presence of di-isopropyl-N-ethylamine yielded a mixture of diastereomers which could be separated into pure diastereomers (10) and (11) using preparative TLC. Similarly, compound (37) on treatment with allyl chloroformate in the presence of di-isopropyl-N-ethylamine yielded a mixture of diastereomers which could be separated by preparative TLC into pure diastereomers (8) and (9).

Provenance & Evidence