Improved process for synthesizing carbapenem intermediates

摘要

This invention relates to the synthesis of a bicyclic ketoester compound of the formula 1 obtained by cyclizing a diazo compound of formula 2: in the presence of a rhodium catalyst. +TR By adding an effective amount of a Lewis acid to the cyclization reaction, the reaction selectively produces the 1-beta methyl isomer, and epimerization of the 1-beta methyl compound to the 1-alpha isomer is minimized.