A catalyst‐free and efficient method for simultaneous olefin hydrogenation and oxidation of arylboronate esters to phenols with hydrazine hydrate and molecular oxygen is presented. The process is based on the utilization of a readily available Lewis acidic arylboron compound, which evades common problems associated with the catalyst‐free aerobic hydrogenation of olefins with diimide. Using an operationally simple procedure, the protocol smoothly delivers phenol derivatives and various alkanes in excellent yields with remarkable functional group compatibility. The method allows the reaction to be scaled up to 1 g of the starting materials.
Highly diastereo- and enantioselective 1,6-addition of β-keto amides to p-quinone methides catalyzed by N-heterocyclic carbenes via ion-pair interaction is developed.
An active acyl donor intermediate generated in situ from an aldehyde by oxidative N-heterocyclic carbene (NHC)-catalysis enables direct acylation of NH-sulfoximine, affording variousN -acylsulfoximinesi ne xcellent yields. The reaction was performed with an inexpensive carbene catalyst and easily accessible bisquinone oxidant. This straightforwardtransformation demonstrated abroad substrate scope with respectt os ulfoximines and aldehydes. Importantly,t he method alloweda midation of several unactivated aliphatic aldehydes in good-to-moderate yields. Preparatives ynthesis of N-acylsulfoximine (up to > 2g) was achieved with this simple method.
Herein, we describe
a method for the catalytic enantioselective
α-amination of α-substituted acyclic 1,3-ketoamides and
1,3-amidoesters that affords the products possessing N-substituted
quaternary stereocenters with a chiral N-heterocyclic carbene (NHC).
The reaction is based on the utilization of an intrinsic Brønsted
base characteristic of NHC that enables the catalytic formation of
a chiral ion pair comprising the enolate and the azolium ion. A series
of challenging open-chain α-substituted 1,3-dicarbonyls are
aminated via this method with ee’s of ≤99%.
Catalysis with N‐heterocyclic carbenes (NHCs) via substrate activation through noncovalent interactions offers a great opportunity to perform organic transformations. Herein, we demonstrate an efficient catalytic method for the 1,6‐conjugate addition of 1,3‐dicarbonyl compounds to para‐quinone methides (p‐QMs) using NHCs as Brønsted‐base catalysts. The method is applicable to a wide range of functionalized substrates with respect to both 1,3‐diketones and p‐QMs. An initial study using chiral NHCs provides information on the feasibility of developing a catalytic enantioselective variant of this reaction.
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