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Preparation of α-amino acids via Ni-catalyzed reductive vinylation and arylation of α-pivaloyloxy glycine.

ABSTRACT: This work emphasizes easy access to α-vinyl and aryl amino acids via Ni-catalyzed cross-electrophile coupling of bench-stable N-carbonyl-protected α-pivaloyloxy glycine with vinyl/aryl halides and triflates. The protocol permits the synthesis of α-amino acids bearing hindered branched vinyl groups, which remains a challenge using the current methods. On the basis of experimental and DFT studies, simultaneous addition of glycine α-carbon (Gly) radicals to Ni(0) and Ar-Ni(ii) may occur, with the former being more favored where oxidative addition of a C(sp²) electrophile to the resultant Gly-Ni(i) intermediate gives a key Gly-Ni(iii)-Ar intermediate. The auxiliary chelation of the N-carbonyl oxygen to the Ni center appears to be crucial to stabilize the Gly-Ni(i) intermediate.

SUBMITTER: Tao X

PROVIDER: S-EPMC8178948 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Preparation of α-amino acids via Ni-catalyzed reductive vinylation and arylation of α-pivaloyloxy glycine.

Tao Xianghua X Chen Yanchi Y Guo Jiandong J Wang Xiaotai X Gong Hegui H

Chemical science 20201027 1

This work emphasizes easy access to α-vinyl and aryl amino acids via Ni-catalyzed cross-electrophile coupling of bench-stable N-carbonyl-protected α-pivaloyloxy glycine with vinyl/aryl halides and triflates. The protocol permits the synthesis of α-amino acids bearing hindered branched vinyl groups, which remains a challenge using the current methods. On the basis of experimental and DFT studies, simultaneous addition of glycine α-carbon (Gly) radicals to Ni(0) and Ar-Ni(ii) may occ ...[more]

PMID: 34163591

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