trifluoroacetic acid lactonizes to furnish α-acetoxyalkyl butenolides (n = 1) and dihydropyranones (n = 2) in 40% overall yield. Conjugate addition to these lactenones and concurrent acetate elimination constitute a general and stereospecific synthesis of the corresponding α-E-alkylidene lactones.
与醛的Alkenylalumination [α-(乙氧基羰基)-β-(吨-butyldimethylsilyloxyalkyl)烯基]
二异丁基铝,得到相应的α- Ž -烷叉基-β'-羟基酯,其在保护和用
三氟乙酸处理lactonizes到配料中α-acetoxyalkyl
丁烯内酯(n = 1)和二氢
吡喃酮(n = 2),总产率为40%。这些内酯的共轭加成和同时消除
乙酸盐构成了相应的α- E-亚烷基内酯的一般和立体有择合成。