Preparation of 5-hydroxy-1-alkenyboronates from 1-alkynylboronates, Cp2ZrCl2/2EtMgBr, and aldehydes.
1-Alkynylboronates form five-membered zirconacycles with Cp(2)ZrCl(2)/2-EtMgBr as indicated by deuterium labeling. The zirconacycles add aldehydes to form seven-membered zirconacycles. Hydrolysis of the latter provides 5-hydroxy-1-alkenylboronates in fair to good isolated yields. Both aliphatic and aromatic aldehydes undergo insertion.
Aziz Quntar
Abed Al
AA
Department of Natural Products and Medicinal Chemistry, School of Pharmacy, Hebrew University in Jerusalem, Jerusalem 91120, Israel.
Srebnik
Morris
M