A Mechanistic Study of Hydroboration of 1-Octene with 1,3,2-Dithiaborolane and 1,3,2-Dithiaborinane. Part 1. Synthesis and Kinetic Studies

Alkylthioboranes 1,3,2-dithiaborolane and 1,3,2-dithiaborinane have been synthesized from the reaction of BH3·SMe2 with 1,2-ethanedithiol and 1,3-propanedithiol, respectively. These heterocyclic boranes disproportionated significantly during their synthesis. The rate constants, and the enthalpies and entropies of the hydroboration reaction of 1-octene with 1,3,2-dithiaborolane and 1,3,2-dithiaborinane have been investigated, and we have shown that hydroboration with these boranes is slow and proceeds via an associative mechanism.Keywords: Hydroboration, disproportionation, boranes, transition statesPDF and Supplementry file attache

A Mechanistic Study of Hydroboration of 1-Octene with 1,3,2-Dithiaborolane and 1,3,2-Dithiaborinane. Part 2. A DFT Study of Disproportionation and Hydroboration

The hydroboration reactions of propene with 1,3,2-dithiaborolane and 1,3,2-dithiaborinane in their ground states have been studied using density functional theory (DFT) at the B3LYP/3-21+G and B3LYP/6-31+G(d) levels. Hydroboration and disproportionation transition states have been determined and activation energies for these transition states were compared. It has been shown that hydroboration reactions require slightly higher activation energies than disproportionation, and yield thermodynamically more stable products.Keywords: Hydroboration, disproportionation, DFT, transition states, potential energy surfacePDF and Supplementry file attache