Haloboration of <i>o</i>‐Alkynyl Phenols Generates Halogenated Bicyclic‐Boronates**

Abstract Benzoxaborinines are intermediates en‐route to bicyclic boronates that important active pharmaceutical ingredients (APIs). Herein, the haloboration of o ‐alkynyl‐phenols using BX 3 (X=Cl or Br) is disclosed as a route form C4‐X‐benzoxaborinines with good functional group tolerance. Computational studies indicated there two similar in barrier mechanisms: (i) double alkyne followed by retro ‐haloboration; (ii) concerted trans ‐haloboration involving an exogenous chloride source. The C4‐halide these benzoxaborinines useful, one‐pot haloboration‐Negishi cross coupling protocol effective alkyl aryl at C4. Therefore this method useful addition toolbox for synthesising bicyclic‐boronates attracting increasing attention APIs.