Halogenated ketenes. 39. A new synthesis for substituted coumarins
作者:William T. Brady、C. H. Shieh
DOI:10.1002/jhet.5570210518
日期:1984.9
A new general synthesis of substituted coumarins is described. The in situ cycloaddition of chloroketenes with α-methoxymethylenecyclohexanones yields (4 + 2) cycloaddition products, 3,4-dihydro-2-pyranones. The chlorine atom is reductively removed and methanol is spontaneously eliminated to yield the 5,6,7,8-tetra-hydrocoumarins. Dehydrogenation of these compounds results in good yields of the substituted
描述了取代香豆素的新的一般合成。中原位环加成用α-methoxymethylenecyclohexanones产率(4 + 2)环加成产物,3,4-二氢-2-吡喃酮chloroketenes的。还原除去氯原子,并自发除去甲醇,得到5,6,7,8-四氢香豆素。这些化合物的脱氢导致取代的香豆素的良好收率。