Synthesis, characterization, and catalytic application of a new chiral P,N-indene ligand derived from (R)-BINOL

Lithiation of 2-dimethylaminoindene followed by quenching with [(R)-(1,1′-binaphthalene-2,2′-diyl)]chlorophosphite and treatment with triethylamine afforded the crystallographically characterized enantiopure P,N-indene 3 in 71% isolated yield. In the course of rhodium coordination chemistry studies involving 3, the formation of the isolable complex [(κ2-P,N-3)(κ1-P,N-3)RhCl] (7) (81%) was observed, thereby confirming the propensity of this new ligand to form LnRh(3)2 complexes. Such coordination chemistry behavior may contribute in part to the generally poor catalytic performance exhibited by mixtures of 3 and rhodium precursor complexes in the asymmetric hydrogenation and hydrosilylation studies described herein.

Graphical abstractWe report the synthesis and characterization of a new chiral P,N-indene ligand, our efforts to develop the rhodium coordination chemistry of this ligand, and the application of this ligand in rhodium-mediated asymmetric alkene hydrogenation and ketone hydrosilylation.Figure optionsDownload full-size imageDownload as PowerPoint slide