Organocatalytic Asymmetric Oxa-Michael-Aldol Cascade

Asymmetric organo-catalysis is the shortened form of molecules catalysis of asymmetric organic synthesis.comparing with metal complexes and enzymes,chemists pay less attention to asymmetric organo-catalysis in the past, and it is one of the most developing research fields in the past few years. Like metal complexes and enzymes,small organic molecules may also promote chemical transformations and give excellent reaction activity and selectivity.However, it has its own advantages: organo-catalysis provides a means of accelerating chemical reactions with a substoichiometric amount of organic molecules,which do not contain a metal element.Principally, asymmetric organocatalytic reactions were, for a long time, considered to be inefficient and limited in scope., In parallel, organometallic catalysts provided a flexible ground for all types of reaction, and thus received disproportionate emphasis.. Though the vast majority of reaction in asymmetric catalysis have to rely on organometallic complexes, and this situation is changing today,and organic catalysis is playing more and more crucial role in organic chemistry,showing a number of advantages over metal-based and bioorganic methods.Nowadays, reactions can be run under an aerobic atmosphere, with wet solents; indeed, we see sometimes that the presence of water is often beneficial to the rate and selectivity of the reaction. The simple operations and ready availability of these mostly inexpensive and stable catalysts - which are better than enzymes or other bioorganic catalysts - makes organocatalysis an attractive method for the synthesis of complex structures. Unlike any earlier developed system, today,organocatalytic reactions provide a strong platform for multicomponent, tandem, or domino-type multistep reactions, which makes it a powerful method.Besides, organo-catalysis are often with fewer toxicity issues, which makes it can be applied to medical industries. What’s more, there is no risk of metal leakage, and no expensive recovery process is required for waste treatment. Nowadays, an increasing number of industrial applications are based on asymmetric organocatalytic reactions because of the advantages:environmentally friendly, green chemistry,the sustainability of the catalysts.