[AlCl<sub>3</sub> + 2THF]: A New and Efficient Catalytic System for Diels−Alder Cycloaddition of α,β-Unsaturated Carbonyl Compounds under Solvent-Free Conditions
[AlCl(3) + 2THF] is a newcatalytic system for the Diels-Aldercycloaddition under SFC and air atmosphere. By using equimolar amounts of reactants, this catalyst prevents the polymerization of the diene and allows the corresponding adducts to be isolated with high regio- and stereocontrol and in excellent yields. [reaction: see text]
Synthetic studies towards gelsemine, I The importance of the antiperiplanar effect in the highly regioselective reduction of non-symmetrical cis-hexahydrophthalimides
作者:Robert J. Vijn、Henk Hiemstra、Joost J. Kok、Martin Knotter、W.Nico Speckamp
DOI:10.1016/s0040-4020(01)87680-8
日期:1987.1
During studies aimed at the total synthesis of gelsemine an exceptional example of regioselectivity has been discovered. cis-Hexahydrophtnalimides, which are non-symmetrical through the presence of one alkyl group (see Figure 1), are reduced by sodium borohydride into the corresponding hydroxy lactams with very high regioselectivity. The corresponding cis-tetrahydrophthalimides exhibit much lower selectivity