Carbonylation of heterocyclic compounds

This dissertation describes the study of carbonylation of heterocyclic compounds. The first chapter serves as an introduction, while the second to fifth chapter describes my contributions to this field.; A series of cobalt-based catalysts or precatalysts (BnCo(CO)4, Co2(CO)8, Co2(CO)8/AIBN, and [Cp 2Ti(THF)2]+[Co(CO)4]- ) are studied for the 2-aryl-2-oxazoline ring expanding carbonylation (REC) under various reaction conditions in the second chapter. The catalytic performances are compared with respect to the chemoselectivity, stereo selectivity, and catalyst turnover numbers. It is believed that either a radical or nucleophic mechanism serves as the major reaction pathway depending on the specific cobalt precatalyst and reaction conditions.; The third chapter discusses a rare exocyclic C-O bond carbonylation involving cycloiminoesters to afford N-acyl-beta-lactams in quantitative to moderate yields over a relatively wide range of temperatures and pressures under the catalysis of Co2(CO)8. It is suggested that nucleophilc attack of the substrate on the Co-acyl bond is a key step in the catalytic reaction.; The role of phosphine in cobalt-catalyzed carbonylative polymerization (COP) of N-alkylaziridines is investigated in the fourth chapter. A series of CH3C(O)Co(CO)3L complexes (L = PCy3, PMe2Ph, PPh3, P(p-F-Ph) 3, P(m-F-Ph)3 and P(o-toly) 3) are synthesized, characterized, and studied as precatalyst. The Co-P bond length primarily responds to the cone angle of the phosphine ligand. The equilibrium constant for CH3C(O)Co(CO)3L + CO ↔ CH3C(O)Co(CO)4 + L mainly depends on the electron-donating ability of the phosphine ligand. The activity difference can not be explained solely by the above equilibrium and is consistent with the competition for the acyl site by the phosphine as nucleophile against aziridine. The production of the beta-lactam byproduct is attributed to catalyst decomposition.; The fifth chapter documents the synthesis and characterization of amphiphilic coblock poly(beta-peptoid)s using the optimized catalyst CH3C(O)Co(CO) 3P(o-Tol)3. Synthesis of amphiphilic block copolymers is realized by sequential addition of different N-alkyl-aziridines under 1000 psi of CO in moderately polar solvent under the monitoring of GCMS and in situ ATR-IR. The block copolymers are characterized using NMR, DSC and GPC techniques. The key for the block copolymer synthesis is the timely addition of the subsequent monomer after the consumption of the previous monomer.