2-Oxazolidone, 3- Reformatsky reaction

Stereoselective Reformatsky reaction. The Reformatsky reaction of the chiral 2-azetidinone 1 with 3-(2-bromopropionyl)-2-oxazolidone (2a) gives essentially a 1 1 mixture of the diastereomers 3a(3 and 3aa. However, introduction of two methyl groups at C4 in 2 markedly improves the (i-diastereoselectivity, as does an increase in the temperature from 0 to 67° (reflux, THF). The highest diastereoselectivity (95 5) is observed with the derivative of 4,4-dibutyl-5,5-pentamethylene-2-oxa-zolidone. The 3p-diastereomer is a useful intermediate to lp-methylcarbapenems.1... 

The Reformatsky reaction has been known for over 100 years a-bromo esters, ketones and amides react with activated zinc dust to give zinc enolates, which can react with carbonyl compounds to give aldol-type products. Recent examples include the reactions with sterically crowded oxazolidone... 

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