The Synthesis Of Various Spirooxindole-pyrro-/Indolizidine- Fused Bisphosphonates Based On The One-pot 1,3-dipole Cycloaddition Of Azomethine Ylide Obtained In Decarboxylative Style To Vinylidenebisphosphonate (VBP)

As a versatile synthon, VBP can be used as dienophile to obtain gem-bisphosphonates via 1,3-dipole cycloaddition of azomethine ylide obtained in decarboxylative style which is one of the most powerful strategies for the synthesis of various five/six-membered heterocycles but less rarely studied than other 1,3-dipoles.The preparation of various spirooxindole-pyrro-/indolizidine-fused bisphosphonates compounds by a multicomponent reaction between aromatic aldehydes/isatins, tetraethyl vinylidenebisphosphonate, and aminal acids in the presence of CeCO2/montmorillonite via one-pot 1,3-dipole cycloaddition of azomethine ylide obtained in decarboxylative style is reported. The clearly proposed mechanism is in line with the experimental data which can strongly prove that azomethine ylide is obtained in decarboxylative style, thus supplying some insight into the underlying mechanisms of these cycloadditions.This methodology shows many notable features, such as broad substrates scope, high efficiency, and good regioselectivity. The targeted moleculars are fully characterized by NMR, MS and IR.Besides, some of methods which is better than that had been reperted were presented, such as the synthsis of MOM-BINOL, (S)-3-formyl-BINOL. A range of isatin derivatives are utilized. Of course, most of the products are purified by column chromatography on silica gel, but several entitled compounds directly precipitated from the reaction system after quenching the reaction which may be amazing in the future.