New coinage metal-catalyzed transformations via carbene intermediatesc-h bond functionalization of metallocenes and carbocyclization reactions

Resumo

The catalytic generation of metal carbenoids has become a powerful synthetic tool. Recently, the use of coinage metals, particularly gold, has allowed the discovery of new reactivity patterns. In this regard, this Ph.D. dissertation reports new coinage metal-catalyzed transformations based on the generation and subsequent trapping of carbene intermediates. In the first chapter, we report the synthesis of functionalized metallocene derivatives through generation of highly electrophilic gold carbenoids that are able to participate in a C-H bond functionalization reaction. Aryl and vinyl-substituted diazo compounds as well as propargylic esters were suitable precursors for the generation of the reactive intermediate. The second chapter focuses on Au(I) and Cu(I) catalyzed [3+2] carbocycloaddition reactions of vinyldiazo compounds and unsaturated substrates such as styrenes, vinylazides and alkenylboronates. These reactions proceeded with complete regioselectivity delivering synthetically useful functionalized cyclopentene derivatives. Finally, in the last chapter we studied the reactivity of vinyldiazo compounds towards allenamides and unbiased allenes. Once again, the cyclization reactions take place with complete regioselectivity. In particular, the regiochemistry observed in cyclizations involving allenamides is very unusual.