Catalytic Hydrogenation of Terminal Alkenes by a (PPP) Pincer-Ligated Cobalt(II) Complex

Abstract

A Co(II) complex, (PP H P)CoI 2 , was synthesized and evaluated as a precatalyst for the hydrogenation of terminal alkenes under mild conditions (1 atm H 2 , ambient temperature) using KBEt 3 H as an activator. This catalytic system was found to be active for terminal alkene substrates, including 1,1′-disubstituted alkenes, and to exhibit modest air and moisture stability. A preliminary investigation into substrate scope and functional group tolerance was performed. Upon the completion of catalytic reactions, the sole metal complex observed was identified as the dimeric species [(PPP)CoH] 2 suggesting that the catalytically active species may be a cobalt hydride monomer.

Synthesis and Characterization of CoIII(TIM) Complexes Bearing Alkenyl or 1-Aza-2-cobalt-cyclopropane Moieties

“…In this regard, redox noninnocent ligands offer a means to overcome such a complication by enabling two-electron redox events in 3d metal complexes . Various Fe- and Co- pincer complexes have been demonstrated to catalyze a variety of organic transformations, such as alkene hydrogenation , and the asymmetric hydrofunctionalization of alkenes and alkynes, as a testament to the success of employing redox active ligands.…”

Facile synthesis of five-membered cyclic RE2P–H iron(0) complexes

“…12 Remarkably, this is not the case for six-membered cyclic P–H phosphanes (phosphinanes), having an N- and/or O-substituted P atom. 13 Also mono- and/or diheteroatom-substituted phosphane complexes with a P–H unit present intrinsic problems, and reported synthetic protocols for N/N, 12,14–31 N/O 32–35 or O/O 36–40 substituted phosphane complexes were individually tailored; a general procedure seems to be absent. Early results of diheteroatom-substituted P–H phosphanes focused on their Fe(CO) 4 complexes (Fig.…”