Nitroaldol (Henry) reaction catalyzed by amberlyst A-21 as a far superior heterogeneous catalyst.
作者:Roberto Ballini、Giovanna Bosica、Paola Forconi
DOI:10.1016/0040-4020(95)00996-5
日期:1996.1
β-Nitroalcohols can be efficiently obtained with the help of AmberlystA-21, as heterogeneous basic catalyst, with or without solvent. This method is farsuperior to the heterogeneouscatalysts previously reported for the nitroaldol (Henry) reaction, in fact it gives higher yields with primary and secondary nitroalkanes, the formation of by-products such as nitroalkenes is avoited even if aromatic
4-substituted-1,2,3,4-tetrahydro-3,3-dimethylisoquinolines. II.
作者:George Bobowski、Jeffrey M. Gottlieb
DOI:10.1002/jhet.5570190102
日期:1982.1
A practical synthesis (Scheme I) is described for the preparation of a series of 4-substituted-3,3-dimethyl-1,2,3,4-tetrahydroisoquinolines (3). Treatment of α-(1-amino-1-methylethyl)arylmethanols or α-(1-amino-1-methylethyl)heteroarylmethanols (5) with aromatic aldehydes gave imines 7 from which amino alcohols 8 were derived by reduction with potassium borohydride. Acid catalyzed cyclization of 8
alpha,alpha-disubstituted-alpha-nitroketones are reduced to the corresponding trisubstituted nitro alcohols in good to excellent yield and enantiomeric excess by borane-dimethylsulfide in the presence of a chiral oxazaborolidine catalyst. Reduction of the nitro alcohols to the corresponding amino alcohols and their subsequent conversion to enantiomerically enriched 4,4,5-trisubstituted oxazoldinones