Active Methylene Compounds in Asymmetric Organocatalytic Synthesis of Natural Products and Pharmaceutical Scaffolds

Last decades have witnessed the golden rush of organocatalysis, which opened an effective and efficient way to high yielding, metal free, stereoselective strategies toward the synthesis of a plethora of natural products. The present review provides an overview of the current achievements of those organocatalytic methodologies in which active methylene compounds have been used as key intermediates. Ranging from covalent to non-covalent activation mode, from monofunctional to bifunctional catalysts, recent results suggest a variety of new powerful tools to accomplish the formal and total synthesis of both the simplest and the most complex natural compounds with facile procedures in high yields and excellent stereoselectivities. At the same time, it is clear how the organocatalytic approach might offer an outstanding and impressive answer to unsolved longstanding synthetic challenges. Finally the possible application to industrial protocols and to the preparation of novel potential drugs has been highlighted.