No abstract

No abstract

No abstract

Azaphospholes are 6 aromatic heterocycles incorporating at least one 2 , 3 -phosphorus atom and one 3 , 3nitrogen atom. This review covers the synthesis, structural characterization, reactions and theoretical calculations of azaphospholes anellated to a six-or five-membered heterocyclic ring, reported during the last 10-12 years. Three synthetic methods, namely [4+1] cyclocondensation, [3+2] cyclocondensation and 1,5-electrocyclization make a variety of these phosphorus heterocycles available. The aromatic character of these compounds has been confirmed by carrying out density functional theory (DFT) calculations. Mainly 1 H, 13 C and 31 P NMR studies have been employed for the structural characterization. Almost all the functionalities present in the azaphosphole ring have been investigated and electrophilic substitution reactions of the 1-unsubstituted compounds and Diels-Alder reactions as well as 1,2-addition reactions to the >C=P-moiety have been accomplished successfully. The stereo-and regioselectivities observed in the Diels-Alder reactions have been explained on the basis of DFT calculations. Cheletropic cycloadducts formed from [4+1] cycloaddition of o-quinones on the 2 , 3 -P atom have been obtained. A variety of coordination compounds formed bycoordination of the 2 , 3 -P atom have been prepared.

No abstract