Microwave-Assisted Olefin Metathesis as Pivotal Step in the Synthesis of Bioactive Compounds

Over the last two decades, olefin metathesis has emerged as a new avenue in the design of new routes for the synthesis of natural products and active pharmaceutical ingredients. In many cases, syntheses based on olefin metathesis strategies provide elegant routes in terms of increasing the overall yields, improving the synthesis scope, and decreasing the number of steps. On the other hand, over the last decade, microwave-assisted chemistry has experienced an incredible development, which rapidly opened new vistas in organic synthesis and in homogeneous catalysis. In this review article, we highlight applications of microwave-heated olefin metathesis reactions as pivotal steps in the total synthesis of biologically active compounds. By drawing selected examples from the recent literature, we aim to illustrate the great synthetic power and variety of metathesis reactions, as well as the beneficial effects of microwave irradiation over conventional heating sources. The majority of the selected applications of microwave-assisted olefin metathesis cover the synthesis of medium-ring cycles, macrocycles, and peptidomimetics by means of ring-closing metathesis (RCM) and cross-metathesis (CM) routes.