Unusual behaviour of some γ- and δ-lactones towards dichloromethylenation using tris(dimethylamino)phosphine–tetrachloromethane
摘要:
Lactones derived from D-glucose, D-mannose and L-ascorbic acid reacted unexpectedly with tris-(dimethylamino)phosphine-tetrachloromethane to give, respectively, dichloroalkene, anomeric vinyl chloride or acyl chloride; this behaviour supports an ionic mechanism for the alkenation.
Dichloromethylenation of Lactones. 6. Efficient Synthesis of Dichloroolefins from Lactones and Acetates Using Triphenylphosphine and Tetrachloromethane
作者:Mohamed Lakhrissi、Yves Chapleur
DOI:10.1021/jo00098a039
日期:1994.9
Triphenylphosphine and tetrachloromethane react cleanly in refluxing tetrahydrofuran with substituted gamma and delta-lactones and some esters to afford the corresponding dichloroolefins in good yields. This new Wittig-type reaction provides an easy entry to this new class of compounds and tolerates a large variety of protecting groups. Application of this methodology to the dichloroolefination of simple lactones, sugar-derived lactones, and other biologically significant lactones is described.