Studies on synthesis of heterocycles and carbocycles by sequential reactions using unsaturated esters

利用高活性的α、β不饱和酯通过顺序键形成新的高效环化反应。乙三羧酸酯、2-膦丙烯酸酯和2-（三氟甲基）丙烯酸酯与偶氮二羧酸二乙酯和PPh3反应可有效地得到吡唑啉。烯丙基乙三羧酸酯和酰胺与TiCl4、TiBr4和AlCl3等路易斯酸反应，立体选择性地高产出3,4-反式卤代基因组乙基2-氧四氢呋喃和吡咯烷衍生物。通过NOE实验测定了其立体化学性质。(E)/(Z)-2-丁烯基酯与AlCl3或FeCl3反应得到3,4-反式4-（1-氯乙基）四氢-2-氧呋喃非对映异构体。(E)/(Z)-2-丁烯基和2-戊烯基酰胺与ni -2反应得到3,4-反式4-（1-碘乙基和丙基）四氢-2-氧吡咯烷非对映异构体。这些反应代表了构建潜在有用化合物的有效方法。

New efficient cyclization reactions using highly reactive alfa,beta-unsaturated esters by sequential bond formations has been developed.The reaction of unsaturated esters such as ethenetricarboxylates, 2-phosphonoacrylate and 2-(trifluoromethyl)acrylate with diethyl azodicarboxylate and PPh3 gave pyrazolines efficiently. Reaction of allyl ethenetricarboxylates and the amides with Lewis acids such as TiCl4, TiBr4 and AlCl3 gave 3,4-trans-halogenomethyl 2-oxotetrahydrofuran and pyrrolidine derivatives stereoselectively in high yields. The stereochemistries were determined by NOE experiments. Reaction of (E)/(Z)-2-butenyl esters with AlCl3 or FeCl3 gave 3,4-trans 4-(1-chloroethyl) tetrahydro-2-oxofuran diastereoisomers stereospecifically. Reaction of (E)/(Z)-2-butenyl and 2-pentenyl amides with ZnI2 gave 3,4-trans 4-(1-iodoethyl and propyl) tetrahydro-2-oxopyrrolidine diastereoisomers stereospecifically.These reactions represent efficient ways to construct potentially useful compounds.