Ruthenium-CatalyzedEnyne Metathesis: An Entry toFunctionalized Azaborine Heterocycles

An unprecedented and green synthetic route for the preparation of functionalized polycyclic azaborine skeletons via a ruthenium-mediated ring-closing enyne metathesis transformation of alkynyl B-anthranilamide (aam) is reported. A variety of B(aam)-bridge enyne derivatives were engaged with the Grubbs-II catalyst, affording the corresponding <i>exo</i>-cyclic compounds (28 novel derivatives). The methodology was efficiently optimized in dimethyl carbonate as green solvent and provided a direct access to functionalized boronated scaffolds displaying dienes which can be further functionalized. In addition, computational analysis of several of the cores synthesized in this study revealed an isoelectronic and isostructural relationship with potential isosteres.