Chiral Synthesis via Organoboranes. 36. Exceptionally Enantioselective Allylborations of Representative Heterocyclic Aldehydes at -100 deg C under Salt-Free Conditions

Article abstract of DOI:10.1021/jo00050a045

Chiral terpenyl-based allylborane reagents (Ter2^*BCH2CH=CH2, 1-3) undergo facile condensation with representative heterocyclic aldehydes (HetCHO) at -100 deg C (in the absence of Mg²⁺ salts) and afford the corresponding homoallylic alcohols (HetCH^*(OH)CH2CH=CH2, 12-19) in enantiomeric purities approaching 100percent ee.A new workup procedure involving 8-hydroxyquinoline (8-HQ) has been utilized for the convenient isolation of the product alcohols.