Diastereo- and regioselective Diels-Alder reactions of 2-phosphaindolizines |
| |
Authors: | Raj K. Bansal Neelima Gupta Surendra K. Kumawat Govind Dixit |
| |
Affiliation: | Department of Chemistry, University of Rajasthan, Jaipur 302 004, India |
| |
Abstract: | 1,3-Bis(alkoxycarbonyl)-2-phosphaindolizines undergo Diels-Alder reactions at the C P- functionality with 2,3-dimethylbutadiene and with isoprene in the presence of sulfur with complete diastereoselectivity. The reaction with isoprene occurs with 100% regioselectivity as well. 3-Ethoxycarbonyl-1-methyl-2-phosphaindolizine, however, fails to undergo Diels-Alder reaction under these conditions. Difference in the dienophilic reactivities of mono- and bis(alkoxycarbonyl) substituted 2-phosphaindolizines and the observed regioselectivity in the Diels-Alder reaction has been rationalized on the basis of DFT calculations. The relative stabilities of the transition structures have been explained on the basis of the NBO analysis. |
| |
Keywords: | Diels-Alder reactions 2-Phosphaindolizines Regioselectivity DFT calculations |
本文献已被 ScienceDirect 等数据库收录! |