Abstract
The alkylative carboxylation of ynamides and allenamides with CO2 and alkylzinc halides catalyzed by a copper catalyst was developed. A variety of alkylzinc halides bearing functional groups were used for this transformation to afford α,β‐unsaturated carboxylic acids, which contain the α,β‐dehydroamino acid skeleton, introducing the corresponding alkyl group and CO2 across the carbon–carbon triple or double bond. This alkylative carboxylation formally consists of Cu‐catalyzed carbozincation of ynamides or allenamides with alkylzinc halides and the subsequent nucleophilic carboxylation of the resulting alkenylzinc species with CO2. This protocol would be a useful method for the synthesis of α,β‐dehydroamino acid derivatives possessing a functionalized alkyl group due to the high regio‐ and stereoselectivity, simple one‐pot procedure as well as the use of CO2 as a starting material.
Double functionalization: Alkylative carboxylation of ynamides and allenamides with CO2 and alkylzinc halides through carbozincation of an unsaturated C−C bond and the subsequent carboxylation of the resulting alkenylzinc halides was developed. This protocol enables carboxylation as well as the introduction of functionalized alkyl groups in a highly regio‐ and stereoselective manner.