Efficient Hydrolysis of Organotrifluoroborates via Silica Gel and Water

Abstract

A general, mild, and efficient method for the hydrolysis of organotrifluoroborates to unveil organoboronic acids using silica gel and H 2 O was developed. This method proved to be tolerant of a broad range of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates as well as structurally diverse aminomethylated organotrifluoroborates. As anticipated, electron-rich substrates provided the corresponding boronic acids more readily than electron-poor substrates, owing to the resonance stabilized difluoroborane intermediate. The method developed was expanded further for the conversion of organotrifluoroborates to the corresponding boronate esters.

Organotrifluoroborates and Monocoordinated Palladium Complexes as Catalysts—A Perfect Combination for Suzuki–Miyaura Coupling

“…[42c] Transformations examined to date include a variety of oxidations,[43] Wittig and related alkenation reactions,[44] reductive aminations,[45] substitution reactions,[46] metal–halogen exchange reactions,[47] condensation reactions,[48] 1,3-dipolar cycloadditions,[49] and cross-coupling reactions. [50]…”

Metal-Free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

“…Initially, catalysts known to convert organotrifluoroborates to organodifluoroboranes were tested. Unfortunately Silica gel, 35 silicon tetrachloride, 36 and boron trifluoride 31,32 did not promote the formation of the desired ynone ( Table 1, entries 1-3). The use of chlorinated Lewis acid catalysts proved to be more successful.…”

Metal‐Free Cross‐Coupling of Arylboronic Acids and Derivatives with DAST‐Type Reagents for Direct Access to Diverse Aromatic Sulfinamides and Sulfonamides

“…[15] Substrate 1a or 6a,which is activatedbyafluoride aniongenerated from DAST or HF,t hen undergoesn ucleophilics ulfuration [16] with intermediate C to providethe correspondingsulfinamide with therelease of intermediate A or D, [17] whichisthen captured by DAST to deliverintermediate B or E. [15] Migration of afluorine atom formsi ntermediate C andB F 4 -,w hich waso bserved by 19 FNMR spectroscopy (see theS upportingI nformation). [20] In conclusion, we have developed asimple and convenient method for the cross-coupling (sulfoxidation) of arylboronic acids and their derivatives with DAST-type reagents under mild and metal-free conditions.T his reaction directly affords various sulfinamides in moderate to good yields within 5min. Phenyltrifluoroborateishydrolyzed by H 2 Ot ogive thec orresponding arylboronica cid, [19] whichi st ransformed throughthe abovementioned pathwaytogive 3aa.…”