Lewis acid-promoted intramolecular reactions of alkenyl ethenetricarboxylates and the corresponding amides have been examined. Reaction of allyl ethenetricarboxylates and the amides with Lewis acids (1-2 equiv) such as TiCl4, TiBr4, AlCl3, and AlBr3 gave 3,4-trans-halogenomethyl 2-oxotetrahydrofuran and pyrrolidine derivatives stereoselectively in high yields. The stereochemistries were determined by NOE experiments. Reaction of alkyl-substituted allylic ethenetricarboxylates with Lewis acids gave chloro 2-oxotetrahydrofurans and pyrans. For some alkyl-substituted substrates, cationic intermediates may be formed under the reaction conditions, and rearranged products have been obtained.

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Lewis Acid-Promoted Cyclization Reactions of Alkenyl Ethenetricarboxylates: Stereoselective Synthesis of 2-Oxotetrahydrofurans and 2-Oxopyrrolidines. -(YAMAZAKI*, S.; FUJINAMI, K.; MAITOKO, Y.; UEDA, K.; KAKIUCHI, K.; J. Org. Chem. 78 (2013) 17, 8405-8416, http://dx.

Triphenylphosphine-Mediated Reaction of Dialkyl Azodicarboxylate with Activated Alkenes Leading to Pyrazolines. -Huisgen zwitterions, derived from triphenylphosphine and azodicarboxylates undergo a cycloaddition reaction with activated alkenes to give the pyrazolines. The method is applicable to ethenetricarboxylates or 2-substituted acrylates. Among 12 phosphines tested in the synthesis of pyrazoline (IIIc), only two phosphines give a yield that is similar to that obtained with PPh 3 . The possible reaction mechanism is discussed, and the selective hydrolysis of pyrazoline (IIIc) followed by decarboxylation or esterification is demonstrated. -(YAMAZAKI*, S.; MAENAKA, Y.; FUJINAMI, K.; MIKATA, Y.; RSC Adv. 2 (2012) 21, 8095-8103, http://dx.