Heterolytic dihydrogen activation with the 1,8-bis(diphenylphosphino)naphthalene/B(C6F5)3 pair and its application for metal-free catalytic hydrogenation of silyl enol ethers
The "frustrated Lewis pair" 1,8-bis(diphenylphosphino)naphthalene/B(C6F5)3 reversibly activates dihydrogen; it serves as an active catalyst for the hydrogenation of silyl enol ethers under mild reaction conditions.
In the presence of Lewisacid, such as SbCl5, SbCl6·NAr3 or Cu(OTf)2, difluorovinyl methylether (1,1-difluoro-2-methoxy-1-alkene) 1 reacted with carbonyl compounds to give O-methylated aldol-type products 3 in good yields, while Lewisacid, such as TMSOTf, TiCl4 or BF3·Et2O, did not work in these reactions. On the other hand, TMSOTf was found an effective catalyst for the reaction of 1 with carbonyl
Axenov, Kirill V.; Kehr, Gerald; Froehlich, Roland, Journal of the American Chemical Society, 2009, vol. 131, p. 3454 - 3455
作者:Axenov, Kirill V.、Kehr, Gerald、Froehlich, Roland、Erker, Gerhard
DOI:——
日期:——
Krolevets, A. A.; Antipova, V. V.; Popov, A. G., Journal of general chemistry of the USSR, 1988, vol. 58, # 10, p. 2023 - 2030
作者:Krolevets, A. A.、Antipova, V. V.、Popov, A. G.、Adamov, A. V.
DOI:——
日期:——
A practical method for activation of commercial lithium hydride: reductive silylation of carbonyl compounds with lithium hydride and chlorotrimethylsilane
作者:Takeshi Ohkuma、Shohei Hashiguchi、Ryoji Noyori
DOI:10.1021/jo00080a035
日期:1994.1
Commercially available lithium hydride, an essentially inert metal hydride, can be activated as a hydride source by an equimolar amount of chlorotrimethylsilane and a catalytic amount of a Zn salt or Zn powder. Aromatic and aliphatic ketones, as well as nonenolizable aldehydes, are reductively converted to the trimethylsilyl ethers of the corresponding alcohols in high yields by treatment with this reagent system in dichloromethane or toluene at 28 to 40 degrees C for 25-50 h. This procedure has many advantages including the safety and low cost of the reagents and operational simplicity and provides a practical method for carbonyl reduction. X-ray induced Auger electron spectroscopy analysis suggests that a Zn(II)I species is the catalyst of the heterogeneous reaction.