Recent Advances in Carbon‐Nitrogen/Carbon‐Oxygen Bond Formation Under Transition‐Metal‐Free Conditions

Abstract

Carbon‐heteroatom bond formation under transition‐metal free conditions provides a powerful synthetic alternative for the efficient synthesis of valuable molecules. In particular, C−N and C−O bonds are two important types of carbon‐heteroatom bonds. Thus, continuous efforts have been deployed to develop novel C−N/C−O bond formation methodologies involving various catalysts or promoters under TM‐free conditions, which enables the synthesis of various functional molecules comprising C−N/C−O bonds in a facile and sustainable manner. Considering the significance of C−N/C−O bond construction in organic synthesis and materials science, this review aims to comprehensively present selected examples on the construction of C−N (including amination and amidation) and C−O (including etherification and hydroxylation) bonds without transition metals. Besides, the involved promoters/catalysts, substrate scope, potential application and possible reaction mechanisms are also systematically discussed.

Boric acid-grafted biochar (BoAB) for the direct amidation of carboxylic acids and amines

“…This deliberate utilization of catalytic surfaces enhances the conversion efficiency and selectivity of the amidation process, paving the way for sustainable and scalable synthetic methods. 7,8 Some examples include group (IV) metal-based Lewis acid (LA) catalysts and boron-based catalysts, which strategically avoid the formation of ammonium carboxylate salts by orchestrating the coordination of the carboxylate group with either the Lewis acid or the metal center. 9…”

Nickel-Catalyzed O-Arylation of Primary or Secondary Aliphatic Alcohols with (Hetero)aryl Chlorides: A Comparison of Ni(I) and Ni(II) Precatalysts

“…The metal-catalyzed C–O cross-coupling of ROH nucleophiles with (hetero)aryl electrophiles, traditionally involving palladium or copper catalysis, offers a useful route to the alkyl (hetero)aryl ether motif found in biologically active compounds such as active pharmaceutical ingredients that is complementary to alternative synthetic protocols (e.g., Mitsunobu, Williamson, S N Ar, and others). More recently, the development of nickel catalysts for such cross-couplings has received attention in the pursuit of an expanded reaction scope within a base–metal catalyst system .…”