Element−Element Additions to Unsaturated Carbon−Carbon Bonds Catalyzed by Transition Metal Complexes

Cascade Triple-Aldehyde Addition of 1,2,3,4-Tetrakis(pinacolatoboryl)but- 2-ene: Stereoselective Synthesis of 2,3-Bis(alkylidene)alkane-1,5-diols

Treatment of (Z)-1,2,3,4-tetrakis(pinacolatoboryl)but-2-ene, prepared from 2,3-bis(pinacolatoboryl)buta-1,3-diene and bis(pinacolato)diboron, with three molar equivalents of aldehyde in toluene at 100 degrees C gave the 2,3-bis(alkylidene)alkane-1,5-anti-diol as a single stereoisomer. The reaction is applicable to both aromatic and alpha-unbranched aliphatic aldehydes. The 1,5-anti-diols were also synthesized by the one-pot preparation/triple-aldehyde addition of the tetraborylated butene. Experimental results for the stepwise treatment of the butene with two types of aldehydes suggest that the rate-determining step of the triple-aldehyde addition is the third allylation.

Addition reactions of E-E and E-H bonds to triple bond of alkynes catalyzed by Pd, Pt, and Ni complexes (E=S, Se)

The synthetic application and mechanistic aspects of transition-metal (Ni, Pd, Pt) catalyzed addition of E-E and E-H (E=S, Se) bonds to alkynes were investigated in detail. This study revealed major factors controlling the selectivity of such addition reactions. A new Ni-based catalytic system with a self-organized nanostructured catalyst has been designed to perform chemical transformation in high yield, under mild conditions.

Rhodium(i)-catalysed conjugate phosphination of cyclic α,β-unsaturated ketones with silylphosphines as masked phosphinides

Nucleophile-activation of the phosphorus(iii)-silicon linkage in silylphosphines generates a nucleophilic phosphorus(iii) equivalent thereby allowing for a rhodium-catalysed conjugate phosphination of beta-substituted alpha,beta-unsaturated acceptors.

Ligand-Controlled, Complementary Stereoselectivity in the Platinum-Catalyzed Intramolecular Silaboration of Alkenes

An intramolecular silaboration of borylsilanyl homoallyl ethers was achieved using a platinum catalyst, giving 1-oxa-2-silacyclopentanes in high yields. The stereoselectivity of the reactions of sec-homoallyl ethers strongly depended on the phosphorus ligand of the platinum catalysts used. The platinum complex bearing the PCyPh2 ligand was found to be the most trans-selective catalyst (trans/cis = 81:19-92:8), whereas a highly cis-selective cyclization was achieved using a platinum catalyst having tris(2,4-di-tert-butylphenyl)phosphite ligand (trans/cis = 8:92-6:94). The synthetic utility of the intramolecular silaboration was demonstrated by the complementary synthesis of a pair of diastereomers of 6-methylheptane-1,3,5-triol.