Methanol Directing the Dual Reactivity of 1,3-Dien-5-ynes under Gold(I) Catalysis: A Computational Study.

Publication date: Available online 30 November 2018Source: Computational and Theoretical ChemistryAuthor(s): Marta Marín-Luna, Iria Bolaño, Carlos Silva López, Olalla Nieto FazaAbstractThe presence of methanol on gold(I)-mediated cycloisomerizations of substituted 1,3-dien-5-ynes provokes the formation of 5-alkoxycyclopentadiene rather than a substituted benzene, which is the isolated product in absence of the alcohol substrate. Calculations indicate that both mechanistic routes start with a 5-endo-dig cyclization of the initial activated-dienyne leading to a bicyclic substrate. This common intermediate then experiments either a tandem ring-expansion/Wagner-Meerwein rearragement process to lead the final benzene or it is attacked by the MeOH molecule leading to the alkoxycyclopentadiene. The kinetic preference along with the high concentration of MeOH used in the reaction would be responsible for the different pathways found in this kind of enynes.Graphical abstract

Source: Computational and Theoretical Chemistry - December 1, 2018 Category: Chemistry Source Type: research