Iridium-catalyzed selective 1,2-hydrosilylation of N-heterocycles

Abstract

A silylene-bridged Ir dimer in situ generated from [Ir(coe)2Cl]2 and Et2SiH2 was found to catalyze the hydrosilylation of N-heteroaromatics to furnish dearomatized azacyclic products with high activity (up to 1000 TONs), excellent selectivity, and good functional group tolerance.

Organoactinide‐Catalyzed Monohydroboration of Carbodiimides

“…In the reaction between the precatalyst Th4 and HBpin,arapid s-bond metathesis was observed, yieldingt he thorium hydride intermediate and Me-Bpin. [17] This reactioni sa lso rapidly observed at room temperature. The addition of one equivalent of DIC resulted in rapid formation of the expected thorium formamidinate compound, which could be readily identified in the 1 HNMR spectrumb yt he appearance of its characteristicm ethine singlet (CÀH)a td = 8.89 ppm.…”

Catalytic Dearomatization of N‐Heteroarenes with Silicon and Boron Compounds

“…Inspired by the study by Harder and co-workers,J eong, Park, and Chang recently developed an Ir-catalyzed selective hydrosilylation of N-heteroarenes. [37] This study represents the first transition-metal-catalyzed 1,2-hydrosilylation of pyridines and other N-heteroaromatic compounds.T he reaction proceeded with high efficiency( up to 1000 turnovers) and ab road substrate scope (Scheme 15). Ar ange of quinolines reacted with Et 2 SiH 2 in the presence of [Ir-(coe) 2 Cl] 2 (7,1 .4 mol %; coe = cyclooctene) to provide the corresponding N-silyl-1,2-dihydroquinolinesi ne xcellent yields.N otably,3 -a nd/or 4-haloquinolines underwent quantitative hydrosilylation in a1 ,2-addition manner without dehalogenation.…”

Catalytic Formation of Silicon–Heteroatom (N, P, O, S) Bonds

“…Encouraged by these results, Chang et al. present a highly selective procedure to yield various N ‐silylated N‐heterocycles by iridium‐catalyzed 1,2‐hydrosilylation . The procedure seems very interesting from a practical point of view, as Si−H addition to quinoline derivatives can also be performed on a large scale to afford the corresponding products in very good yields.…”