Transition metals in organic chemistry: From Suzuki cross-coupling to the Diels-Alder cycloaddition.

摘要

This thesis is an investigation of the use of transition metals to catalyze organic reactions. In the first part of the thesis, Pd(0)-catalyzed Suzuki cross-coupling reactions between 2,3-dibromonorbornadiene and aryl boronic acids were explored as a means to generate symmetrical and unsymmetrical aryl substituted norbornadienes. Optimization of the reaction conditions were determined to be: Pd2(dba)3 (0.5 mol%), tBu 3P (1.4 mol%), CsF in THF. In general, electron-rich aryl boronic acids lead to high yielding Suzuki products while electron-deficient aryl boronic acids produced 2,3-diarylnorbornadienes in lower yields.; In the second part of the thesis, a cationic Rh(I) species generated in situ from [RhCl(COD)]2 (2.5 mol%) and AgSbF6 (5.0 mol%) in acetone was investigated as a catalyst for the Diels-Alder cycloaddition of alkynyl halides. The cationic Rh(I) species was shown to be a highly active catalytic species for the intramolecular [4+2] cycloaddition. The Diels-Alder cycloaddition occurred smoothly and was unaffected by the nature of the halide. The intermolecular Diels-Alder cycloaddition with internal alkynyl halides was not successful under the conditions described for the intramolecular variant.