A New Diastereoselective Synthesis of Enantiomerically Pure 1,2-Oxazine Derivatives by Addition of Lithiated Methoxyallene to Chiral Nitrones
作者:Wolfgang Schade、Hans-Ulrich Reissig
DOI:10.1055/s-1999-2662
日期:1999.5
Addition of lithiated methoxyallene 2 to nitrones provided hydroxylamine derivatives which usually undergo very fast cyclization to 3,6-dihydro-2H-1,2-oxazines. Chiral nitrones 5, 8, or 10 which furnished 1,2-oxazines 6, 9, and 11 with excellent syn diastereoselectivities are of particular interest. By precomplexation of nitrone 5b with diethylaluminum chloride 1,2-oxazine 6b was produced with excellent