Abstract
A study of the stereo- and face selectivity of the cycloaddition reactions of several mono- and disubstituted alkenes with 4-hydroxymethyl-3.4.5.6-tetrahydropyridine 1-oxide has been carried out. The addition reactions have displayed a very high degree of face selectivity in the range 13-48 1 Use of dimethyl methylenemalonate as a protective group in nitrone cycloaddition reactions has been demonstrated. The invertomeric analysis revealed that the bicyclic cycloadducts remain predominantly as the cis-fused isomer, which leads to the formation of synthetically important second-generation cyclic aldonitrones via peracid oxidation One interesting finding was that treatment of the cycloadducts with two equivalents of peracid afforded the cyclic N-hydroxy lactams. presumably via further oxidation of the aldonitrones. The piperidine ring has been elaborated by cycloaddition reaction of the second-generation nitrones with several alkenes, which in most cases gave the cycloadducts in a stereoselective manner (C) 2009 Elsevier Ltd All rights reserved