Lewis acid-promoted intramolecular reactions of alkenyl ethenetricarboxylates and the corresponding amides have been examined. Reaction of allyl ethenetricarboxylatesand the amides with Lewis acids (1-2 equiv.) such as TiCl4, TiBr4, AlCl3 and AlBr3 gave 3,4-transhalogenomethyl 2-oxotetrahydrofuran and pyrrolidine derivatives stereoselectively in high yields.1Stereospecificity of cyclization reaction of (E) and (Z)-2-alkenyl esters and amides of ethenetricarboxylate has also been examined. Reaction of (E)/(Z)-2-butenyl esters with AlCl3 or FeCl3 at room temperature 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.The stereochemistries of cyclized products were determined by NOE experiments, further transformation and proposed reaction mechanism.(E)/(Z)-2-butenyl or (E)/(Z)-2-pentenyl amides of ethenetricarboxylate undergo an intramolecular ene reaction at room temperature gradually. Heating of the Z-amides at 80 �C gave 3,4-cis ene adducts stereoselectively. Heating of the E-amides at 80 �C gave 3,4-cis and trans ene adduct mixtures. Reference1. Yamazaki, S.; Fujinami, K.; Maitoko, Y.; Ueda, K.; Kakiuchi, K. J. Org. Chem. 2013  , 78, 8405.

Lewis acid-promoted cyclization reactions of alkenyl ethenetricarboxylates: Stereoselective synthesis of 2-oxotetrahydrofurans and 2-oxopyrrolidines

248th National Meeting (2014)

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