Download or read book Application of Chameleon Catalyst and VAPOL VANOL Imidodiphosphorimidate Catalysts in Asymmetric Catalysis written by Aliakbar Mohammadlou and published by . This book was released on 2020 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: In chapter 1 the discovery of chameleon catalysts was discussed. The chameleon catalyst was defined as an agent that can catalyze different reactions with different mechanisms. We have found that a chiral biaryl borate ester with two VANOL ligands and one boron complex is an extremely active catalyst for the epoxidation of aldehydes and the aziridination of imines. Mechanistic investigation revealed that this catalyst can catalyze epoxidation aziridination reactions with a different mechanism. We have shown that the aforementioned catalyst acts as a Lewis acid in the epoxidation of aldehydes and Bronsted acid in the aziridination of imines. X-ray structural analysis, Hammett study, and 11B-NMR study support our hypothesis.In chapter two the discovery and utility of the aluminum VAPOL catalyst and aluminum VANOL catalyst were explored. We have found that a chiral biaryl aluminum with two VAPOL ligands and one aluminum complex is an extremely active catalyst for the epoxidation of aldehydes with diazo acetamide. The excellent performance of aluminum VAPOL catalyst has also shown in the total synthesis of (−)-tedanalactam which was accomplished in only 5 steps with excellent enantioinduction in 37% overall yield. The aluminum catalyst also performed well in the aziridination reaction transforming the imine into the aziridine with good yield and excellent ee. We believe the aluminum catalyst also acts as a chameleon; however, more experiments are required to show the chameleon behavior of these complexes.In chapter three, inspired by Benjamin List's imidodiphosphorimidate catalysts, VANOL imidodiphosphorimidate (VIP) and VAPOL imidodiphosphorimidate (VAPIP) catalysts were synthesized. X-ray structural analysis aided us to perform crystal engineering on VIP derivatives and design a highly efficient VIP catalyst for the asymmetric halonium-ion induced spiroketalization. VIP catalysts were also explored in the asymmetric intramolecular Schmidt reaction; however, no asymmetric induction was observed after exploring the reaction with a library of these catalysts.
Download or read book Catalytic Asymmetric Synthesis Enabled by VANOL VAPOL Borox Catalysts written by Hong Ren and published by . This book was released on 2013 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Methods in Asymmetric Synthesis written by Michelangelo Gruttadauria and published by John Wiley & Sons. This book was released on 2011-09-27 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers advances in the methods of catalytic asymmetric synthesis and their applications. Coverage moves from new materials and technologies to homogeneous metal-free catalysts and homogeneous metal catalysts. The applications of several methodologies for the synthesis of biologically active molecules are discussed. Part I addresses recent advances in new materials and technologies such as supported catalysts, supports, self-supported catalysts, chiral ionic liquids, supercritical fluids, flow reactors and microwaves related to asymmetric catalysis. Part II covers advances and milestones in organocatalytic, enzymatic and metal-based mediated asymmetric synthesis, including applications for the synthesis of biologically active molecules. Written by leading international experts, this book consists of 16 chapters with 2000 References and illustrations of 560 schemes and figures.
Download or read book Application of Chiral Borates in Asymmetric Catalysis and Chiral Resolution written by Xiaopeng Yin and published by . This book was released on 2018 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
