Iron-Catalyzed Borylation of Alkyl, Allyl, and Aryl Halides: Isolation of an Iron(I) Boryl Complex

Abstract

Activation of B2pin2 with tBuLi facilitates the Fe-catalyzed borylation of alkyl, allyl, benzyl, and aryl halides via the formation of Li[B2pin2(tBu)] (1). The reaction of 1 with a representative iron phosphine precatalyst generates the unique iron(I) boryl complex [Fe(Bpin)(dpbz)2] (2).

Easy access to nucleophilic boron through diborane to magnesium boryl metathesis

“…These data are strongly reminiscent of the chemical shifts reported for the species formed, though not isolated, by the addition of tert -BuLi to B 2 pin 2 in THF solution ( δ 39.1, 6.4 p.p.m. )47. Crystallographic analysis confirmed compound 9 to be a magnesium complex of a [pinB-Bpin( n- Bu)] − anion coordinated to Mg(1) through the O(1) and O(3) centres of the two pinacolato boron moieties (Fig.…”

Selective Boryl‐Anion Migration in a Vinyl sp2−sp3 Diborane Induced by Soft Borane Lewis Acids

“…[6] Since B(C 6 F 5 ) 3 can activate alkenes and alkynes even in the presence of certain oxo functionalities,the ability of B(C 6 F 5 ) 3 to trigger the 1,2-boryl migration was explored. The successful formation of [2] À was indicated by 11 BNMR spectroscopy,w hich showed two new resonances:o ne at 37.3 ppm (three-coordinate boron) and the other at 4.8 ppm (four-coordinate boron), analogous to the spectrum reported for [(Ph)B 2 Pin 2 ] À (39.2 and 4.0 ppm, respectively).…”

The Role of Low Valent Transition Metal Complexes in Homogeneous Catalysis: An EPR Investigation

“…The EPR spectrum of this complex (Fig. 2g) was broadened in comparison to the spectra of the related [FeX(dpbz) 2 ] (X = Cl, Br, tol) complexes and was lacking in resolvable hyperfine structure [42]. Despite DFT calculations predicting that most (* 87 %) of the electron spin density was located primarily on the Fe atom, the broad line-width was explained as a result of superhyperfine and quadrupolar coupling to 31 P and 10,11 B respectively.…”