title: How large is the conjugative stabilization of diynes?
abstract: The conjugation stabilization energies of dienes and diynes are considerably larger than estimates based on heat of hydrogenation differences between 1,3-butadiyne and 1-butyne as well as between 1,3-butadiene and 1-butene. Such comparisons do not take into account the counterbalancing hyperconjugative stabilization of the partially hydrogenated products by their ethyl groups. When alkyl hyperconjugation is considered, the conjugation stabilization of diynes ( approximately 9.3 kcal/mol) is found by two methods (involving isomerization of nonconjugated into conjugated isomers and heats of hydrogenation) to be larger than that of dienes ( approximately 8.2 kcal/mol).
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Jarowski
authors.forename: M D
authors.initials: MD
authors.lastname: Wodrich
authors.forename: C S
authors.initials: CS
authors.lastname: Wannere
authors.forename: P V R
authors.initials: PV
authors.lastname: Schleyer
authors.forename: K N
authors.initials: KN
authors.lastname: Houk