TY - JOUR
T1 - Selective Boryl-Anion Migration in a Vinyl sp2−sp3 Diborane Induced by Soft Borane Lewis Acids
AU - Fasano, Valerio
AU - Cid, Jessica
AU - Procter, Richard J.
AU - Ross, Emily
AU - Ingleson, Michael J.
PY - 2018/10/1
Y1 - 2018/10/1
N2 - An intramolecular 1,2-boryl-anion migration from boron to carbon has been achieved by selective activation of the π system in [(vinyl)B2Pin2)]− using “soft” BR3 electrophiles (BR3=BPh3 or 9-aryl-BBN). The soft character is key to ensure 1,2-migration proceeds instead of oxygen coordination/B−O activation. The BR3-induced 1,2-boryl-anion migration represents a triple borylation of a vinyl Grignard reagent using only B2Pin2 and BR3 and forms differentially protected 1,1,2-triborylated alkanes. Notably, by increasing the steric bulk at the β position of the vinyl Grignard reagent used to activate B2Pin2, 1,2-boryl-anion migration can be suppressed in favor of intermolecular {BPin}− transfer to BPh3, thus enabling simple access to unsymmetrical sp2−sp3 diboranes.
AB - An intramolecular 1,2-boryl-anion migration from boron to carbon has been achieved by selective activation of the π system in [(vinyl)B2Pin2)]− using “soft” BR3 electrophiles (BR3=BPh3 or 9-aryl-BBN). The soft character is key to ensure 1,2-migration proceeds instead of oxygen coordination/B−O activation. The BR3-induced 1,2-boryl-anion migration represents a triple borylation of a vinyl Grignard reagent using only B2Pin2 and BR3 and forms differentially protected 1,1,2-triborylated alkanes. Notably, by increasing the steric bulk at the β position of the vinyl Grignard reagent used to activate B2Pin2, 1,2-boryl-anion migration can be suppressed in favor of intermolecular {BPin}− transfer to BPh3, thus enabling simple access to unsymmetrical sp2−sp3 diboranes.
KW - 1,2-migration
KW - boranes
KW - borylation
KW - Grignard reagents
KW - Lewis acids
UR - http://www.scopus.com/inward/record.url?scp=85053437516&partnerID=8YFLogxK
U2 - 10.1002/anie.201808216
DO - 10.1002/anie.201808216
M3 - Article (Academic Journal)
C2 - 30102471
AN - SCOPUS:85053437516
SN - 1433-7851
VL - 57
SP - 13293
EP - 13297
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 40
ER -