Trineopentylphosphine: a conformationally flexible ligand for the coupling of sterically demanding substrates in the Buchwald-Hartwig amination and Suzuki-Miyaura reaction.

Trineopentylphosphine (TNpP) in combination with palladium provides a highly effective catalyst for the Buchwald-Hartwig coupling of sterically demanding aryl bromides and chlorides with sterically hindered aniline derivatives. Excellent yields are obtained even when both substrates include 2,6-diisopropyl substituents. Notably, the reaction rate is inversely related to the steric demand of the substrates.

Stereospecific Suzuki, Sonogashira, and Negishi coupling reactions of N-alkoxyimidoyl iodides and bromides.

A high-yielding stereospecific route to the synthesis of single geometric isomers of diaryl oxime ethers through Suzuki coupling of N-alkoxyimidoyl iodides is described. This reaction occurs with complete retention of the imidoyl halide geometry to give single E- or Z-isomers of diaryl oxime ethers. The Sonogashira coupling of N-alkoxyimidoyl iodides and bromides with a wide variety of terminal alkynes to afford single geometric isomers of aryl alkynyl oxime ethers has also been developed.

An electron-rich proazaphosphatrane for isocyanate trimerization to isocyanurates.

A facile synthesis of the new electron-rich, sterically hindered proazaphosphatrane shown above is described herein. This proazaphosphatrane catalyzes the cyclotrimerization of a wide variety of isocyanates to isocyanurates under mild conditions with unprecedentedly fast reaction times, giving moderate to high product yields. It is also shown that this proazaphosphatrane can be recycled up to 5 times.

Advantageous use of tBu2P-N=P(iBuNCH2CH2)3N in the Hiyama coupling of aryl bromides and chlorides.

An efficient catalytic route to biaryls by employing (generally) only 0.25 mol % of Pd(OAc)(2) and 0.5 mol % of 1 in the Hiyama coupling reaction is reported.

Catalysis of mukaiyama aldol reactions by a tricyclic aluminum alkoxide Lewis acid.

The Mukayiama aldol reaction of aldehydes is efficiently accomplished with a low concentration of the dimeric alumatrane catalyst 2 at mild or subambient temperatures. Our protocol tolerates a wide variety of electron-rich, neutral, and deficient aryl, alkyl, and heterocyclic aldehydes. A wide variety of enol silyl ethers are also tolerated.