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US 5,493,018 AGranted
Process for synthesizing carbapenem intermediates using a rhodium catalyst and lewis acid
AssigneeMerck & Co., Inc.
InventorsThomas Meng-Han Liu, Joseph E. Lynch, Ralph P. Volante
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Abstract
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. ##STR1## 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.
Claims17
A process for synthesizing a compound of the formula:
- ##STR9## in which M is a carboxyl protecting group and P represents H or a hydroxyl protecting group,
- comprising cyclizing the compound:
- ##STR10## in the presence of a rhodium catalyst and a catalytic quantity of a Lewis acid which is effective for reducing formation of the 1-.alpha.methyl isomer to form compound 1.
Dependencies are inferred from the claim text.