7554-10-1Relevant articles and documents
Preparation of α-amino acids: via Ni-catalyzed reductive vinylation and arylation of α-pivaloyloxy glycine
Chen, Yanchi,Gong, Hegui,Guo, Jiandong,Tao, Xianghua,Wang, Xiaotai
, p. 220 - 226 (2021/01/14)
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.
Ruthenium-catalyzed one-pot carbenoid N-H insertion reactions and diastereoselective synthesis of prolines
Deng, Qing-Hai,Xu, Hai-Wei,Yuen, Angella Wing-Hoi,Xu, Zhen-Jiang,Che, Chi-Ming
supporting information; experimental part, p. 1529 - 1532 (2009/04/07)
Aryl- and aliphatic-substituted 3-hydroxyprolines and various other amino esters are conveniently prepared by [RuCI2(p-cymene)] 2-catalyzed one-pot intramolecular and intermolecular carbenoid N-H insertion reactions, respectively, and the prolines are formed with high diastereoselectivities. The catalytic reactions are tolerant toward air/moisture, and the product yields are insensitive to the organic solvents used.
