Highly(≥98%) Stereo- and Regioselective Trisubstituted Alkene Synthesis of Wide Applicability via 1-Halo-1-alkyne Hydroboration-Tandem Negishi-Suzuki Coupling or Organoborate Migratory Insertion Protocol.

ABSTRACT: (Z)-1-Halo-1-alkenylboranes (7), preparable in 82-90% yields as ≥98% isomerically pure compounds via hydroboration of 1-halo-1-alkynes, have been converted to a wide range of trisubstituted alkenes via three different routes in the tail-to-head (T-to-H) direction, i.e., (i) Palladium-catalyzed Negishi-Suzuki tandem alkenylation, (ii) treatment of 7 with organolithium or Grignard reagents to generate α-bromo-1-alkenylboronate complexes (10) that can undergo migratory insertion of a carbon group (R²) to form (E)-alkenylboranes (11) with inversion of alkene configuration (≥98% inversion), followed by fluoride-promoted Suzuki alkenylation, and (iii) Negishi coupling to generate (Z)-alkenylboranes (8) in ≥98% reten

SUBMITTER: Xu S 

PROVIDER: S-EPMC3781585 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature