Harnessing Alkylpyridinium Salts as Electrophiles in Deaminative Alkyl–Alkyl Cross-Couplings
作者:Shane Plunkett、Corey H. Basch、Samantha O. Santana、Mary P. Watson
DOI:10.1021/jacs.9b00111
日期:2019.2.13
A Negishicross-coupling of alkylpyridinium salts and alkylzinc halides has been developed. This is the first example of alkyl-alkyl bond formation via cross-coupling of an alkyl amine derivative with an unactivated alkyl group, and allows both primary and secondary alkylpyridinium salts to react with primary alkylzinc halides with high functional group tolerance. When combined with formation of the
Chiral boronic esters are a class of versatile building blocks. We describe herein an asymmetric nickel-catalyzed borylative coupling of terminal alkenes with nonactivated alkyl halides. The success of this asymmetric reaction is ascribed to the application of a chiral anionic bisoxazoline ligand. This study provides a three-component strategy to access α- and β-stereogenic boronic esters from easily
The present invention provides an aqueous emulsion composition excellent in heat resistance, water resistance, hot water resistance, boiling water resistance, and viscosity stability and also excellent in stain resistance. The present invention relates to an aqueous emulsion composition including an aqueous emulsion (D) and a cyclic acid anhydride (E). The aqueous emulsion (D) includes a polymer (X) having an ethylenically unsaturated monomer (B), a polyvinyl alcohol resin (A), and water. At least one selected from the polyvinyl alcohol resin (A) and the polymer (X) has, in a main chain thereof, a structural unit derived from a monomer (C) represented by the following formula (I), (II), (III), or (IV).
(The definitions of the symbols in the formulae are omitted.)
The present invention provides an aqueous emulsion composition excellent in heat resistance, water resistance, hot water resistance, boiling water resistance, and viscosity stability and also excellent in stain resistance. The present invention relates to an aqueous emulsion composition including an aqueous emulsion (D) and a cyclic acid anhydride (E). The aqueous emulsion (D) includes a polymer (X) having an ethylenically unsaturated monomer (B), a polyvinyl alcohol resin (A), and water. At least one selected from the polyvinyl alcohol resin (A) and the polymer (X) has, in a main chain thereof, a structural unit derived from a monomer (C) represented by the following formula (I), (II), (III), or (IV).
(The definitions of the symbols in the formulae are omitted.)
Mechanistic Studies on the Organocatalytic α‐Chlorination of Aldehydes: The Role and Nature of Off‐Cycle Intermediates
Herein we report the isolation and characterization of aminal intermediates in the organocatalytic α‐chlorination of aldehydes. These species are stable covalent ternary adducts of the substrate, the catalyst and the chlorinating reagent. NMR‐assisted kinetic studies and isotopic labeling experiments with the isolated intermediate did not support its involvement in downstream stereoselective processes