Mechanism and Linear Energy Relationships in the Kinetics of Formation of Bicyclononane Derivatives from 1,3,5-Trinitrobenzene, Benzoylacetones, and Base

Article abstract of DOI:10.1021/jo00208a007

The kinetics and mechanism of cyclization of the anionic ? complex obtained from the reaction of sym-tri-nitrobenzene (TNB) and benzoylacetone (BA) in the presence of triethylamine (NEt3) have been studied in Me2SO-H2O (80percent v/v).The order of the reaction has been found to be zero in TNB, unity in BA, fractional in NEt3, and negative and nonintegral in H⁺NEt3.When the solvent is changed from Me2SO-H2O (80percent v/v) to CH3CN the order with respect to TNB is zero, BA is unity, NEt3 is unity, and H⁺NEt3 is negative and nonintegral.The fractional order with respect to NEt3 in Me2SO-H2O (80percent v/v) was found to be due to the involvement of Me2SO in proton abstraction and hence in cyclization.DMF also brought about the cyclization in a similar manner.The plot of rate constants for the formation of bicyclic complexes from substituted benzoylacetones and TNB vs. ?⁺/? concaved downward indicating a change in the rate determining step.