99417-55-7

Diisopropyl 2-Allyl-1,3,2-dioxaborolane-4,5-dicarboxylate can be used as a reagent for the asymmetric allylic borylation of aldehydes to generate homoallylic alcohols.

Diisopropyl 2-Allyl-1,3,2-dioxaborolane-4,5-dicarboxylate is prepared by the reaction of Triisopropyl Borate and Allylmagnesium Bromide in Et2O  followed by an acidic extractive workup and direct esterification with diisopropyl tartrate (DIPT) (eq 1).

Allylboronates are typically handled as a solution in toluene (0.5-1.0 M)  and transferred by syringe under an inert atmosphere. The reagent, stored neat or as a solution in toluene  over 4? molecular sieves under an argon atmosphere in a refrigerator (-20 °C), is stable for several months.  In the presence of water, (1) rapidly hydrolyzes to DIPT and the achiral allylboronic acid.