Rhodium(I) complexes of β-diketonates and related ligands as hydrosilylation catalysts
作者:William R. Cullen、Eugene B. Wickenheiser
DOI:10.1016/0022-328x(89)87281-x
日期:1989.7
The complexes (OO)Rh(CH2CH2)2 ((OOH) = FcC(O)CH2C(O)CH3, PhC(O)CH2C(O)CH3, 1,2-(CH3CO)(OH)C6H4, 3-benzoyl-(+)-camphor) are catalysts for the hydrosilylation of PhMeCO with Ph2SiH2. The optical yield from the reaction catalyzed by the camphor derivative is too low to measure. Only low optical yields (max 8.7% e.e.) are obtained from the same reaction by using similar in situ catalysts with ligands
alkylation of aminophenols to enantiopure tertiary aminophenols, which are useful chiral ligands for metal-catalysed asymmetric reactions, is reported. This very simple synthetic methodology, through reduction or alkylation of an intermediate benzoxazine, was performed in mild conditions, suitable for the conservation of the configuration of the stereogenic centres. Some crystalline aminophenols show the
Asymmetric reduction of enantiopure imines with zinc borohydride: stereoselective synthesis of chiral amines
作者:Cristina Cimarelli、Gianni Palmieri
DOI:10.1016/s0957-4166(00)00209-3
日期:2000.6
The first application of zincborohydride in the reduction of enantiopure imines for the stereoselective preparation of both the enantiomers of secondary amines is described. A possible explanation of the stereoselectivity and of the reaction mechanism is suggested on the basis of theoretical calculations.
methods available till now. The sense of asymmetricinduction has been explained and confirmed in agreement with the results previously obtained by hydride reduction of the same substrates. In some cases this procedure is complementary to the reductive one, allowing the preparation of the diastereomers less abundant in the reduction. The reaction allows the synthesis of one or the other of the two diastereomers
作者:E. Peter Kündig、Candice Botuha、Gilles Lemercier、Patrick Romanens、Lionel Saudan、Sylvie Thibault
DOI:10.1002/hlca.200490054
日期:2004.3
Three different routes were probed for the synthesis of enantiomerically enriched 2-(1-aminoethyl)phenols and their methyl ethers. The first route centers on diastereoselective nucleophile addition to chiral imines. The second route has as key steps the enantioselective reduction of a ketone followed by nucleophilic substitution, and the third route involves a diastereoselective imine reduction. The