[4+2] Cycloaddition of 1-phosphono-1,3-butadiene with azo- and nitroso-heterodienophiles
作者:Jean-Christophe Monbaliu、Jacqueline Marchand-Brynaert
DOI:10.1016/j.tetlet.2008.01.050
日期:2008.3
Under microwave activation, diethyl 1-phosphono-1,3-butadiene (1) reacted with t-butyl azodicarboxylate (2) and o-nitrosotoluene (5) to furnish quantitatively [4+2] cycloadducts, 3-phosphono-3,6-dihydro-1,2-pyridazine (3) and 6-phosphono-3,6-dihydro-1,2-oxazine (6), respectively. Selective oxidation and/or reduction of 6 led to functionalized 6-aminophosphonic derivatives in cyclic (7, 8) and aliphatic series (9, 10). Intermediate 10 may be cyclized into 2-phosphono-2,5-dihydro-1-pyrrole (12). (C) 2008 Elsevier Ltd. All rights reserved.