Nonstatistical Dynamic Effects in the Thermal C<sup>2</sup>–C<sup>6</sup> Diels–Alder Cyclization of Enyne–Allenes
作者:Debabrata Samanta、Mehmet Emin Cinar、Kalpataru Das、Michael Schmittel
DOI:10.1021/jo302524a
日期:2013.2.15
The Diels-Alder (DA) reaction channel of the thermal C-2-C-6 (Schmittel) cyclization of enyne-allenes is studied computationally and experimentally evaluating the influence of temperature on product ratios. Remote substituents at the alkyne terminus influence the mechanism of the C-2-C-6/DA cyclization steering it either to a stepwise or a concerted course. Temperature independent product ratios, selectivity of product formation, and computational results obtained at (U)BLYP/6-31G(d) level unveil a mechanism that is strongly controlled by nonstatistical dynamics.