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

以高活性α，β-不饱和酯为原料，通过顺序键的形成，开发了一种新的高效的环化反应。不饱和酯如三甲酸乙酯、2-膦酸甲酯和2-三氟甲基丙烯酸酯与偶氮二甲酸二乙酯和PPh3反应生成了吡唑啉类化合物。烯丙基三羧酸酯和酰胺类化合物与TiCl4、TiBr4和AlCl3等Lewis酸反应，高产率地立体选择性地合成了3，4-反式卤代甲基2-氧代四氢呋喃和吡咯烷衍生物。通过NOE实验确定了其立体化学组成。(E)/(Z)-2-丁烯酯与AlCl3或FeCl3反应生成3，4-反式-4-(1-氯乙基)四氢-2-氧代呋喃非对映异构体。(E)/(Z)-2-丁烯基和2-戊烯基酰胺与锌离子反应得到3，4-反式-4-(1-碘乙基和丙基)四氢-2-氧代吡咯烷非对映异构体，这些反应是合成潜在有用化合物的有效途径。

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.