An easy access to highly substituted trispiroheterocycles – Synthesis of novel pyrazolo-1,4-dioxa-spiro[4,5]decane grafted spiro-oxindolopyrrolidines via a sequential multicomponent reaction

A facile one-pot sequential four-component synthesis of highly substituted trispiro heterocyclic system involving [3 + 2]-cycloaddition of azomethine ylides as the key step is described. The protocol provides a mild reaction condition, high yield of the products, high regioselectivity, and operational simplicity to assemble complex structural entity in a single operation. The structure of the product was confirmed by spectroscopic techniques, elemental and high-resolution mass spectrum analysis