Synthesis of alkyltrifluoroborates
A new synthetic method for the preparation of potassium organotrifluoroborates through nucleophilic substitution of potassium bromo- and iodomethyltrifluoroborates is described. Potassium halomethyltrifluoroborates have been prepared via in situ reaction of n-BuLi with dibromo- and diiodomethane, respectively, in the presence of trialkyl borates, followed by treatment with KHF2.
G. A. Molander, J. Ham, Org. Lett., 2006, 8, 2031-2034.
Activated pyridine borane complexes (Py·BH2X) are capable of hydroborating alkenes at room temperature. An unusual hydroboration mechanism is discussed. Hydroboration of alkynes with Py·BH2I selectively affords the monoadducts. The preparation of synthetically useful potassium alkyltrifluoroborate salts is described.
J. M. Clay, E. Vedejs, J. Am. Chem. Soc., 2005, 127, 5766-5767.
A copper-catalyzed β-boration of α,β-unsaturated carbonyl compounds with tetrahydroxydiborane allows direct, efficient access to boronic acids and their derivatives. Various α,β-unsaturated amides, ketones and esters are converted to the corresponding β-trifluoroborato compounds in good to excellent yields.
G. A. Molander, S. A. McKee, Org. Lett., 2011, 13, 4648-4687.
Ketone-, ester-, and amide-containing potassium trifluoroboratohomoenolates were prepared in good yields from the corresponding unsaturated carbonyl compounds. They are effective coupling partners in the Suzuki-Miyaura reaction with various electrophiles including electron-rich and electron-poor aryl bromides and -chlorides.
G. A. Molander, D. E. Petrillo, Org. Lett., 2008, 10, 1795-1798.