Microwave assisted organic synthesis-a review

Microwave irradiation has been successfully applied in organic chemistry. Spectacular accelerations, higher yields under milder reaction conditions and higher product purities have all been reported. Indeed, a number of authors have described success in reactions that do not occur by conventional heating and even modifications of selectivity (chemo-, regio- and stereoselectivity). The effect of microwave irradiation in organic synthesis is a combination of thermal effects, arising from the heating rate, superheating or “hot spots” and the selective absorption of radiation by polar substances. Such phenomena are not usually accessible by classical heating and the existence of non-thermal effects of highly polarizing radiation—the “specific microwave effect”—is still a controversial topic. An overview of the thermal effects and the current state of non-thermal microwave effects is presented in this critical review along with a view on how these phenomena can be effectively used in organic synthesis.

Microwaves in organic synthesis. thermal and non-thermal microwave effects

Centro de Quı́mica-Fı́sica Molecular (CQFM) and Institute of Nanosciences and Nanotechnology (IN), Departamento de Engenharia Quı́mica e Biológica, Instituto Superior Técnico, 1049-001 Lisboa, Portugal, REQUIMTE, Departamento de Quı́mica, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal, and iMed.UL, Faculdade de Farmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal

More sustainable approaches for the synthesis of N-based heterocycles.

Recent progress in the synthesis and chemistry of azetidinones

Clay catalyzed synthesis of imines and enamines under solvent-free conditions using microwave irradiation

Microwave-assisted rapid synthesis of α-amino-β-lactams

Enantiospecific synthesis of β-lactams via cycloaddition

3,4-Disubstituted-1-arylazetidin-2-ones can be prepared in an enantiospecific manner by the annelation of Schiff bases from optically active glyceraldehyde acetonide and their stereochemistry determined from n.m.r. studies on lactones prepared from these β-lactams by molecular rearrangement.

S. S. Bari

Papers

Microwave-assisted rapid synthesis of α-amino-β-lactams

Enantiospecific synthesis of β-lactams via cycloaddition

Absolute configuration of α-substituted β-lactams from D-glyceraldehyde acetonide

A convenient synthesis of azetidine-2,3-diones (α-Keto-β-Lactams)☆

Synthesis of α-halo and α-deuterio-β-lactams