Ni‐Catalyzed α‐Alkylation of Unactivated Amides and Esters with Alcohols by Hydrogen Auto‐Transfer Strategy

• Published in: ChemSusChem 2018-11, Vol.11 (22), p.3911-3916
• Main Authors: Midya, Siba P., Rana, Jagannath, Pitchaimani, Jayaraman, Nandakumar, Avanashiappan, Madhu, Vedichi, Balaraman, Ekambaram
• Format: Article
• Language: English
• Subjects: Alcohol; Alcohols; Alkylation; Amides; Catalysis; Esters; homogeneous catalysis; Hydrogen; hydrogen transfer; Nickel
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201801443

A transition‐metal‐catalyzed borrowing hydrogen/hydrogen auto‐transfer strategy allows the utilization of feedstock alcohols as an alkylating partner, which avoids the formation of stoichiometric salt waste and enables a direct and benign approach for the construction of C‐N and C−C bonds. In this study, a nickel‐catalyzed α‐alkylation of unactivated amides and ester (tert‐butyl acetate) is carried out by using primary alcohols under mild conditions. This C−C bond‐forming reaction is catalyzed by a new, molecularly defined nickel(II) NNN‐pincer complex (0.1–1 mol %) and proceeds through hydrogen auto‐transfer, thereby releasing water as the sole byproduct. In addition, N‐alkylation of cyclic amides under Ni‐catalytic conditions is demonstrated. A nickel(II) NNN‐pincer‐catalyzed α‐alkylation of unactivated amides and ester (tert‐butyl acetate) is carried out by using primary alcohols under mild conditions proceeding by a borrowing hydrogen/hydrogen auto‐transfer mechanism. This C−C bond‐forming reaction releases water as the sole byproduct. N‐Alkylation of cyclic amides under Ni‐catalytic conditions is also demonstrated.