Study based on electronic descriptors of the diastereoselective aza-diels-alder cycloaddition of [(1r)-10-(n,n-diethylsulfamoyl)isobornyl] 2h-azirine-3-carboxylate to e,e-1,4-diacetoxy-1,3-butadiene

Abstract

Cycloaddition of chiral [(1R)-10-(N,N-diethylsulfamoyl)isobornyl] 2H-azirine-3-carboxylate to E,E-1,4-diacetoxy-1,3-butadiene shows complete diatereoselectivity giving a single cycloadduct (-)-(2S,5R,6R)-6-[(1R)-10-(N,N-diethylsulfamoyl)isobornyloxycarbonyl]-1-azabicyclo[4.1.0]hept-3-ene-2,5-diyldiacetate. Our main objective is to identify electronic/steric parameters capable of describing the observed tendencies of this reaction. The results of the calculations conclude that: even though the steric factors can play an important role at the initial steps of the reaction, at the transition states the behavior of several electronic parameters; like hardness, polarizability, aromaticity, charge transfer, etc is decisive enough to justify the obtained product. Finally, this work summarizes an exhaustive analysis of electronic descriptors and empirical reactivity principles, reaching a definitive and comprehensive explanation to the observed experimental result.