An expedient ultrasonic assisted one-pot four component synthesis of novel ferrocene grafted pyrrolidine heterocycles via [3 + 2]-cycloaddition of azomethine ylides

An expedient one-pot four component ultrasonic assisted synthesis of novel ferrocene grafted spiro-pyrrolidine heterocycles via [3 + 2]-cycloaddition of azomethine ylides is described. The protocol provides a mild reaction conditions, high yield of product in short reaction time, high regioselectivity, operational simplicity and applicable to a wide variety of ferrocene derived dipolarophiles for the efficient synthesis of ferrocene appended heterocycles. The structures of cycloadducts were confirmed by spectroscopic analysis. X-ray analysis of the products adds conclusive support to the proposed structure.