Asymmetric Organocatalytic Homologation: Access to Diverse Chiral Trifluoromethyl Organoboron Species.

A broad range of aliphatic, aromatic, and heterocyclic boronic acids were successfully homologated using trifluorodiazoethane in the presence of BINOL derivatives to provide the corresponding chiral trifluoromethyl containing boronic acid derivatives in high yields and excellent enantioselectivity. The in situ conversion of the chiral transient boronic acids to the corresponding alcohols or β-CF3 carboxylates are also demonstrated.

Organocatalytic Synthesis of α-Trifluoromethyl Allylboronic Acids by Enantioselective 1,2-Borotropic Migration.

Chiral α-substituted allylboronic acids were synthesized by asymmetric homologation of alkenylboronic acids using CF/TMS-diazomethanes in the presence of BINOL catalyst and ethanol. The chiral α-substituted allylboronic acids were reacted with aldehydes or oxidized to alcohols in situ with a high degree of chirality transfer. The oxygen-sensitive allylboronic acids can be purified via their isolated diaminonaphthalene (DanH)-protected derivatives.