One-pot catalytic asymmetric borylation of unsaturated aldehyde-derived imines; functionalisation to homoallylic boronate carboxylate ester derivativesElectronic supplementary information (ESI) available: Further experimental details, ReactIR spectra, all 1H, 13C and 11B NMRs, and X-ray crystallographic details. CCDC 1040392 (2a), 1040393 (2b), 1040394 (2e), 1040395 (2h) and 1040594 (2j). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4ob02657h

The β-borylation reaction of α,β-unsaturated aldehyde-derived imines, formed in situ , has been studied using a one-pot methodology, as a route to β-boryl aldehydes. The instability of the β-boryl aldehydes meant that derivatisation was required and routes to both acetal derivatives and homoallylic boronates were examined. β-Boryl acetals were also found to be unstable, however, the formation of homoallylic boronate derivatives using an in situ imine hydrolysis-Wittig olefination protocol was found to be suitable, resulting in an efficient synthesis with high enantiomeric excesses. The β-borylation reaction of α,β-unsaturated aldehyde-derived imines, formed in situ , has been studied using a one-pot methodology, as a route to homoallylic boronates through the β-boryl aldehydes.