Enantiospecific Trifluoromethyl‐Radical‐Induced Three‐Component Coupling of Boronic Esters with Furans

Alkynyl Moiety for Triggering 1,2‐Metallate Shifts: Enantiospecific sp2–sp3 Coupling of Boronic Esters with p‐Arylacetylenes

The enantiospecific coupling of secondary and tertiary boronic esters to aromatics has been investigated. Using p-lithiated phenylacetylenes and a range of boronic esters coupling has been achieved by the addition of N-bromosuccinimide (NBS). The alkyne functionality of the intermediate boronate complex reacts with NBS triggering the 1,2-migration of the group on boron to carbon giving a dearom...

Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence

Coupling reactions between benzylamines and boronic esters have been investigated. ortho-Lithiated benzylamines react with boronic esters and a N-activator to afford ortho-substituted benzylic boronic esters with formal 1,1'-benzylidene insertion into the C-B bond. The reaction occurs by a SN2' elimination and 1,2-metalate rearrangement of the N-activated boronate complex to afford a dearomatiz...

Enantiospecific sp2–sp3 Coupling of ortho‐ and para‐Phenols with Secondary and Tertiary Boronic Esters

The coupling of ortho- and para-phenols with secondary and tertiary boronic esters has been explored. In the case of para-substituted phenols, after reaction of a dilithio phenolate species with a boronic ester, treatment with Ph3 BiF2 or Martin's sulfurane gave the coupled product with complete enantiospecificity. The methodology was applied to the synthesis of the broad spectrum antibacterial...

Enantiospecific, regioselective cross-coupling reactions of secondary allylic boronic esters.

Some Items of Interest to Process R&D Chemists and Engineers ■ COPPER-CATALYZED TRIFLUOROMETHYLATION OF BORONIC ACIDS WITH TRIFLUOROMETHYL IODIDE A mild method for the cross-coupling of arylboronic acids with CF3I via the merger of photoredox

A mild method for the cross-coupling of arylboronic acids with CF3I via the merger of photoredox (to generate CF3 radical) and Cu catalysis (to generate reactive Cu−aryl species) was developed by Professor Sanford and her co-worker of University of Michigan (J. Am. Chem. Soc. 2012, 134, 9034− 9037). Potassium carbonate was found a base of choice for the promotion of transmetalation in DMF solve...