Nucleophilic additions of lithiated allylphenylsulfone to nitrones: experimental and theoretical investigations
作者:Pedro Merino、Vanni Mannucci、Tomás Tejero
DOI:10.1016/j.tet.2005.01.043
日期:2005.3
The nucleophilic addition of lithiated allylphenylsulfone to nitrones at -80 degrees C proceeds exclusively a to the phenylsulfonyl group affording anti adducts in high yield. At 0 degrees C isoxazolidines are obtained with complete all-trans selectivity. The formation of these compounds involves isomerization of the allylsulphonyl moiety to give a transient vinylsulfone that then undergoes a subsequent intramolecular Michael addition. The addition to several nitrones has been studied and theoretical calculations have been refined to accurately explain the selectivity of the allylation reaction. (c) 2005 Elsevier Ltd. All rights reserved.