Substrate Controlled [3+3] Relay Catalytic Cyclization of α-(3-Isoindolinonyl) Propargylic Alcohols with 5-Aminoisoxazoles

Two different skeletons have been constructed by cyclization of alpha-(3-isoindolinonyl) propargylic alcohols with 5-aminoisoxazoles bearing different N-substituents under the relay catalysis of Bronsted acid and Lewis acid. This method provided spiro-isoindolinone-dihydropyridines with moderate to high yields (up to 99 %) as well as isoxazolo[4,5-b]pyridines in moderate to good yields (up to 86 %). The structures of two products were determined by X-ray crystal structural analyses. Moreover, fluorescence testing proved that one of the isoxazolo[4,5-b]pyridines exhibited aggregation induced emission (AIE) effect. Finally, the control experiments revealed the possible reaction mechanism. Relay catalytic [3+3] cyclization of alpha-(3-isoindolinonyl) propargylic alcohols with 5-aminoisoxazoles bearing different N-substituents provide novel spiro-isoindolinone-dihydropyridines as well as isoxazolo[4,5-b]pyridines in moderate to good yields. The structures of two products are determined by X-ray crystal structural analyses. image