作者:Shizheng Zhu、Guifang Jin、Weimin Peng、Qichen Huang
DOI:10.1016/s0040-4020(03)00344-2
日期:2003.4
4-dihydro-2H pyrans. These products are formed by elimination and addition of the alcohol to the products of the normal hetero Diels–Alder reaction (2-alkoxyl-3-trifluoroacetyl-2,3-dihydro-2H pyrans). In contrast, 1,3-dipolar cycloaddition of ROCHCHCOCF3 with ArCHN(O)Me proceeds via a Z-endo transition state to give regio- and stereospecific 4-trifluoroacetyl substituted isoxazolidines and their derivatives
β-三氟乙酰基乙烯基醚ROCH = CHCOCF 3作为亲二烯体与α,β-不饱和羰基化合物平稳反应,生成意外的2-烷氧基-5-三氟乙酰基-3,4-二氢-2 H吡喃。这些产物是通过消除醇并将其添加到常规杂Diels-Alder反应产物(2-烷氧基-3-三氟乙酰基-2,3-二氢-2 H吡喃)中而形成的。与此相反,ROCHCHCOCF的1,3-偶极环加成3与ArCHN(O)Me经由前进ž -内型过渡状态,得到区域选择性和立体有择的4-三氟乙酰基取代的异恶唑烷和它们的衍生物。