[EN] HYDROGENATION AND DEHYDROGENATION CATALYST, AND METHODS OF MAKING AND USING THE SAME [FR] CATALYSEUR D'HYDROGÉNATION ET DE DÉSHYDROGÉNATION, ET SES PROCÉDÉS DE FABRICATION ET D'UTILISATION
Mild and Selective Cobalt‐Catalyzed Chemodivergent Transfer Hydrogenation of Nitriles
作者:Zhihui Shao、Shaomin Fu、Mufeng Wei、Shaolin Zhou、Qiang Liu
DOI:10.1002/anie.201608345
日期:2016.11.14
Herein, we describe a selective cobalt‐catalyzed chemodivergent transferhydrogenation of nitriles to synthesize primary, secondary, and tertiary amines. The solvent effect plays a key role for the selectivity control. The general applicability of this procedure was highlighted by the synthesis of more than 70 amine products bearing various functional groups in high chemoselectivity. Moreover, this
Cobalt Phosphino-α-Iminopyridine-Catalyzed Hydrofunctionalization of Alkenes: Catalyst Development and Mechanistic Analysis
作者:Wan-Yi Chu、Ryan Gilbert-Wilson、Thomas B. Rauchfuss、Maurice van Gastel、Frank Neese
DOI:10.1021/acs.organomet.6b00457
日期:2016.9.12
A family of CoCl2(PNpy) complexes were prepared, where PNpy = 2-iminopyridyl-phosphine ligands derived from amino-alkyl and aminoaryl phosphines and 2-keto- and 2-formylpyridines. Reduction of CoCl2(PNpy) complexes in the presence of PPh3 gave CoH(PNpy)(PPh3) and CoMe(PNpy)(PPh3), which were active for hydrofunctionalization of alkenes. According to DFT calculations, the CoMe(PNpy)(PPh3) complexes are best described as Co (II) derivatives of the anion [PNpy](-), with a labile PPh3 coligand. Metalation of Na[(Ph2)PC(2)N(H)py] gave the dimers [CoCl2(P(C2)N(H)py)](2). Monomeric complexes catalyze hydrosilylation of 1-octene with Ph2SiH2, with the CoCl2 ((iPr2)P(C3)N(H)py)/2NaBEt(3)H system exhibiting the highest rate and selectivity for anti-Markovnikov product. In situ NMR studies established the following: (i) silanes protonolyze catalyst precursors to give the. Co-silylcomplexes Co (SiR3) ((Ph2)P(C6H4)N(Ph)py)(pph(3)), (ii) alkenes compete with PPh3 to give Co(SiHPh2)((Ph2)P(C6H4)N(Ph)py) (eta(2)-alkene), (iii) ethylene inserts into the Co-Si bond to give Co(CH2CH3SiR3)((Ph2)P(C6H4)N(Ph)py)(pph(3)).