Stereoselective Synthesis of Amphoteric α-Haloalkenyl Boronates by Halogenative Semipinacol Rearrangement of B(MIDA)-Propargylic Alcohols.

The facile synthesis of stereo-defined and transformable functionality-enriched building blocks is of great importance in modern organic chemistry, as it allows the rapid and divergent assembly of complex molecules. Herein a halogen electrophile (N-bromosuccinimide and N-iodosuccinimide) initiated semipinacol rearrangement reaction of B(MIDA)-propargylic alcohols (MIDA=N-methyliminodiacetyl) by aryl migration towards the synthesis of amphoteric α-haloalkenyl boronates in moderate to good yields with excellent stereoselectivities is reported. The value of the products is evidenced by their ability to undergo divergent conversions to polysubstituted alkenes through manipulation of the C-B and C-X (X=Br, I) bonds and the carbonyl group.