Chun-Hui Xing

Controlled Pd(0)/t-Bu3P-catalyzed Suzuki cross-coupling polymerization of AB-type monomers with PhPd(t-Bu3P)I or Pd2(dba)3/t-Bu3P/ArI as the initiator.

Controlled Pd(0)/t-Bu(3)P-catalyzed Suzuki cross-coupling polymerizations of AB-type monomers via the chain-growth mechanism with an ArPd(t-Bu(3)P)I complex as the initiator are described. ArPd(t-Bu(3)P)I complexes, either prepurified or generated in situ from Pd(2)(dba)(3)/t-Bu(3)P/ArI (dba = dibenzylideneacetone) without separation/purification, were found to be efficient initiators in general for the controlled Suzuki cross-coupling polymerization, with narrow polydispersity indexes (PDIs) of 1.13-1.35 being observed. The Pd(2)(dba)(3)/t-Bu(3)P/p-BrC(6)H(4)I combination was identified as a highly robust initiator system, with PDIs of ≤1.20 in general and as low as 1.13 being obtained. Higher number-average molecular weights (M(n)) were achieved without a significant increase in the PDI (from 1.14 for a polymer with a M(n) = 9500 to 1.20 for a polymer with M(n) = 31,400) by using a smaller amount of the Pd(2)(dba)(3)/t-Bu(3)P/p-BrC(6)H(4)I initiator in the polymerization.

Orthoplatinated triarylphosphite as a highly efficient catalyst for addition reactions of arylboronic acids with aldehydes: low catalyst loading catalysis and a new tandem reaction sequence.

Readily available, air/moisture-stable orthoplatinated triarylphosphite catalyzes the addition reactions of arylboronic acids with aldehydes with the catalyst loading as low as 0.01%. It also cataylzes a new tandem reaction of arylboronic acids with alpha,beta-unsaturated aldehydes to form 1,3-diaryl-1-propanols. Our study provides a new paradigm for the application of orthoplatinated triarylphosphites, and may pave the road to develop other Pt(II) catalysts for such addition reactions and other tandem reactions with such addition reactions as part of the reaction sequence.

Fluorenone Synthesis by Palladacycle-Catalyzed Sequential Reactions of 2-Bromobenzaldehydes with Arylboronic Acids

A new, anionic four-electron donor-based (type I) palladacycle-catalyzed sequential reaction of 2-bromobenzaldehydes with arylboronic acids based on the addition reaction, cyclization via C-H activation-oxidation sequence is described. Our study provided an efficient access to a variety of substituted fluorenones/indenofluorenediones from readily available arylboronic acids and 2-bromobenzaldehydes.

Rhodium(I)/Diene-Catalyzed Addition Reactions of Arylborons with Ketones

Rh(I)/diene-catalyzed addition reactions of arylboroxines/arylboronic acids with unactivated ketones to form tertiary alcohols in good to excellent yields are described. By using C(2)-symmetric (3aR,6aR)-3,6-diaryl-1,3a,4,6a-tetrahydropentalenes as ligands, the asymmetric version of such an addition reaction, with up to 68% ee, was also realized.

Electron‐Poor, Fluoro‐Containing Arylboronic Acids as Efficient Coupling Partners for Bis(1,5‐cyclooctadiene)nickel(0)/Tricyclohexylphosphine‐Catalyzed Cross‐Coupling Reactions of Aryl Arenesulfonates

The use of electron-poor, fluoro-containing arylboronic acids as general coupling partners for nickel(0) /tricyclohexylphosphine-catalyzed cross-coupling of aryl arenesulfonates is described. Electron-poor fluoro-containing arylboronic acids were found to react, faster than electron-rich/neutral arylboronic acids, with (4-methoxyphenyl)(4-methylbenzenesulfonato-κO)bis(tricyclohexylphosphine)nickel. Bis(1,5-cyclooctadiene)nickel(0)/tricyclohexylphosphine, (4-methoxyphenyl)(4-methylbenzenesulfonato-κO)bis(tricyclohexylpho sphine)nickel and bis(tricyclohexylphosphine)nickel (II) bromide were all found to be efficient catalysts/catalyst precursors.