Experimental and Computational Investigation of Facial Selectivity Switching in Nickel-Diamine-Acetate-Catalyzed Michael Reactions.

Autor:	Sohtome Y; Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.; RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan., Komagawa S; Elements Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan., Nakamura A; Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan., Hashizume D; RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan., Lectard S; Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan., Akakabe M; Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.; RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan., Hamashima Y; Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan., Uchiyama M; RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.; Elements Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan., Sodeoka M; Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.; RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Jazyk:	angličtina
Zdroj:	The Journal of organic chemistry [J Org Chem] 2023 Jun 16; Vol. 88 (12), pp. 7764-7773. Date of Electronic Publication: 2023 Feb 22.
DOI:	10.1021/acs.joc.2c02732
Abstrakt:	Chiral Ni complexes have revolutionized both asymmetric acid-base and redox catalysis. However, the coordination isomerism of Ni complexes and their open-shell property still often hinder the elucidation of the origin of their observed stereoselectivity. Here, we report our experimental and computational investigations to clarify the mechanism of β-nitrostyrene facial selectivity switching in Ni(II)-diamine-(OAc) 2 -catalyzed asymmetric Michael reactions. In the reaction with a dimethyl malonate, the Evans transition state (TS), in which the enolate binds in the same plane with the diamine ligand, is identified as the lowest-energy TS to promote C-C bond formation from the Si face in β-nitrostyrene. In contrast, a detailed survey of the multiple potential pathways in the reaction with α-keto esters points to a clear preference for our proposed C-C bond-forming TS, in which the enolate coordinates to the Ni(II) center in apical-equatorial positions relative to the diamine ligand, thereby promoting Re face addition in β-nitrostyrene. The N-H group plays a key orientational role in minimizing steric repulsion.
Databáze:	MEDLINE
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