Rhodium and Platinum Catalyzed Cycloadditions from Propargylic Esters and Ethers

Download or read book Rhodium and Platinum Catalyzed Cycloadditions from Propargylic Esters and Ethers written by and published by . This book was released on 2013 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade has witnessed a "gold rush" due to the novel [tau tau]-acidity of gold. On the other hand, rhodium is well known for traditional organometallic reactivities such as oxidative addition, reductive elimination, and carbonylation, which makes rhodium widely utilized in industrial processes such as hydroformylation and Monsanto acetic acid synthesis. My Ph.D. research combines [tau tau]-acidity of rhodium with traditional reactivities of rhodium. In particular, we use [tau tau]-acidic Rh-complexes to activate propargylic esters and ethers for cycloadditions. Propargylic esters can undergo either 1,3- or 1,2-acyloxy migration in the presence of rhodium to form allenes and vinyl metal carbenes respectively. By taking advantage of the Rh-catalyzed 1,3-acyloxy migration, I developed a [5+1] cycloaddition starting from cyclopropyl propargylic esters. By taking advantage of Rh-catalyzed 1,2-acyloxy migration, I contributed to the synthesis of 7- and 8-membered rings starting from vinyl propargylic esters. Vinyl metal carbenes could also be obtained from propargylic esters tethered with a nucleophile. By employing either platinum or rhodium metal complexes, I developed a tandem indole annulation and [4+3] cycloaddition with dienes and furans involving vinyl metal carbene intermediates. Biologically interesting bisindoles were also synthesized through a similar indole annulation followed by intermolecular nucleophilic trap of external indoles.