Divergent Elementoboration: 1,3-Haloboration versus 1,1-Carboboration of Propargyl Esters.

ABSTRACT: This work showcases the 1,3-haloboration reaction of alkynes in which boron and chlorine add to propargyl systems in a proposed sequential oxazoliumborate formation with subsequent ring-opening and chloride migration. In addition, the functionalization of these propargyl esters with dimethyl groups in the propargylic position leads to stark differences in reactivity whereby a formal 1,1-carboboration prevails to give the 2,2-dichloro-3,4-dihydrodioxaborinine products as an intramolecular chelate. Density functional theory calculations are used to rationalize the distinct carboboration and haloboration pathways. Significantly, this method represents a metal-free route to highly functionalized compounds in a single step to give structurally complex products.

SUBMITTER: Wilkins LC 

PROVIDER: S-EPMC6055811 | biostudies-other | 2018 May

REPOSITORIES: biostudies-other