Photo-/electrochemical catalyzed oxidative R 1 -H/R 2 -H cross-coupling with hydrogen evolution has become an increasingly important issue for molecular synthesis. The dream of construction of C−C/C−X bonds from readily available C− H/X−H with release of H 2 can be facilely achieved without external chemical oxidants, providing a greener model for chemical bond formation. Given the great influence of these reactions in organic chemistry, we give a summary of the state of the art in oxidative R 1 -H/R 2 -H cross-coupling with hydrogen evolution via photo/electrochemistry, and we hope this review will stimulate the development of a greener synthetic strategy in the near future.

N,O-aminals, molecules bearing a geminally N,O-substituted (stereogenic) carbon center, have been recently recognized as an important class of building blocks in organic synthesis. As direct precursors of imines and iminium ions, N,O-aminals were converted through asymmetric organocatalysis or metal catalysis to diverse enantiomerically enriched compounds including N-heterocycles. Furthermore, cyclic N,O-hemiaminals acted as acyclic amino aldehyde surrogates, which were transformed to enantioenriched products otherwise challenging to access. Finally, cyclic N,O-aminals were formed in situ as key intermediates in asymmetric catalysis. In this review, we introduce a wide array of catalytic asymmetric protocols involving the use of four distinct types of N,O-aminals as starting materials or key intermediates.

A highly selective, environmentally friendly, and scalable electrochemical protocol for the construction of α-acyloxy sulfides, through the synergistic effect of self-assembly-induced C­(sp3)–H/O–H cross-coupling, is reported. It features exceptionally broad substrate scope, high regioselectivity, gram-scale synthesis, construction of complex molecules, and applicability to a variety of nucleophiles. Moreover, the soft X-ray absorption technique and a series of control experiments have been utilized to demonstrate the pivotal role of the self-assembly of the substrates, which indeed is responsible for the excellent compatibility and precise control of high regioselectivity in our electrochemical protocol.

Asymmetric C(sp)-C(sp(2)) bond formation to give enantiomerically enriched 1,3-butadienyl-2-carbinols occurred through a homoallenylboration reaction between a 2,3-dienylboronic ester and aldehydes under the catalysis of a chiral phosphoric acid (CPA). A diverse range of enantiomerically enriched butadiene-substituted secondary alcohols with aryl, heterocyclic, and aliphatic substituents were synthesized in very high yield with high enantioselectivity. Preliminary density functional theory (DFT) calculations suggest that the reaction proceeds via a cyclic six-membered chairlike transition state with essential hydrogen-bond activation in the allene reagent. The catalytic reaction was amenable to the gram-scale synthesis of a chiral alkyl butadienyl adduct, which was converted into an interesting optically pure compound bearing a benzo-fused spirocyclic cyclopentenone framework.

Dioxygen-triggered oxidative cleavage of C–S bonds has been achieved, delivering a series of N-containing heterocyclic compounds that are frequently found in pesticides and pharmaceuticals.