Cyano-borrowing: titanium-catalyzed direct amination of cyanohydrins with amines and enantioselective examples

Copper-Catalyzed Aza-Benzyl Transfer Michael Addition via C-C Bond Cleavage

A non-noble Cu-catalyzed transfer aza-benzyl Michael addition via the C-C bond cleavage of aza-benzyl alcohols has been disclosed. The unstrained C(sp³)-C(sp³) bond of an alcohol was selectively cleaved. This aza-benzyl transfer strategy provides a selective and environmentally benign approach for the C-alkylation of α,β-unsaturated carbonyl compounds that employs readily available alcohols as carbon nucleophiles and is characterized by a wide range of substrates and good to excellent yields.

Development of ProPhenol/Ti(IV) Catalyst for Asymmetric Hydroxylative Dearomatization of Naphthols

By development of ProPhenol/Ti(IV) catalysts, a catalytic enantioselective hydroxylative dearomatization of naphthols is achieved by using TBHP as a simple oxidative reagent. The side coordinative chain equipped on the C1-position of β-naphthols plays an important role for initiating this asymmetric hydroxylative reaction, which might be a result of the proper cocoordination effects to the titanium center in the catalyst. A reasonable catalytic cycle is proposed, the catalytic system is applied to a reasonable range of this type of phenolic compound, and related concise transformations are carried out.

Sliver-Catalyzed 1,3-Aza-Benzyl Migration of Allyl Alcohol

Carbon migration of alkenyl alcohols has been recognized as an increasingly viable methodology in organic synthesis. Herein, we disclose a silver-catalyzed 1,3-aza-benzyl migration of allyl alcohols by utilizing chelation-assisted selective cleavage of an unstrained C(sp³)-C(sp³) bond. This approach provides an available, efficient, high atom-economic, and environmentally benign procedure, leading to alkylation products with broad substrate scopes and excellent yields. The migration proceeds via a one-pot, two-step process involving a free-state alkyl metal species.

Alkynyl Borrowing: Silver-Catalyzed Amination of Secondary Propargylic Alcohols via C(sp3)-C(sp) Bond Cleavage

The silver-catalyzed alkynyl borrowing amination of secondary propargyl alcohols via C(sp³)-C(sp) bond cleavage has been developed. This new strategy was based on the β-alkynyl elimination of propargyl alcohols and alkynyl as the borrowing subject. This alkynyl borrowing amination featured high atom economy, wide functional group tolerance, and high efficiency.

Copper-catalyzed transfer methylenation via C(sp3)–C(sp3) bond cleavage of alcohols

Transfer Methylenation: A copper-catalyzed transfer methylenation via the cleavage of unstrained C(sp3)-C(sp3) bonds is developted. This is a de novo report for transfer hydrocarbylation between alcohols and carbonyl compounds.

2-Pyridinylmethyl borrowing: base-promoted C-alkylation of (pyridin-2-yl)-methyl alcohols with ketones via cleavage of unstrained C(sp3)–C(sp3) bonds

2-Pyridinylmethyl Borrowing: Transition-metal-free 2-pyridinylmethyl borrowing C-alkylation of alcohols access to ketones is developed. This unstrained C(sp3)–C(sp3) bonds cleavage of unactivated alcohols avoids the use of transition metals.

Tris(pentafluorophenyl)borane-Catalyzed Formal Cyanoalkylation of Indoles with Cyanohydrins

Despite the significant achievements related to the C3 functionalization of indoles, cyanoalkylation reactions continue to remain rather limited. We herein report on the formal C3 cyanoalkylation of indoles with cyanohydrins in the presence of a tris(pentafluorophenyl)borane (B(C₆F₅)₃) catalyst. It is noteworthy that cyanohydrins are used as a cyanoalkylating reagent in the present reaction, even though they are usually used as only a HCN source. Mechanistic investigations revealed the unique reactivity of the B(C₆F₅)₃ catalyst in promoting the decomposition of a cyanohydrin by a Lewis acidic activation through the coordination of the cyano group to the boron center. In addition, a catalytic three-component reaction using indoles, aldehydes as a carbon unit, and acetone cyanohydrin that avoids the discrete preparation of each aldehyde-derived cyanohydrin is also reported. The developed methods provide straightforward, highly efficient, and atom-economic access to various types of synthetically useful indole-3-acetonitrile derivatives containing α-tertiary or quaternary carbon centers.

Transition-metal free cyano 1,3 migration of unsaturated cyanohydrins

A novel approach of transition-metal-free cyano 1,3-migration of β,γ- and α,β-unsaturated cyanohydrins is reported.