Synthesis of Functionalized Organotrifluoroborates via the 1,3-Dipolar Cycloaddition of Azides
摘要:
We have successfully prepared potassium azidoalkyltrifluoroborates from the corresponding halogen compounds in 94 - 98% yields through a nucleophilic substitution reaction with NaN3. In the presence of various alkynes and Cu(I) as a catalyst, these azidotrifluoroborates easily formed 1,4-disubstituted organo-[1,2,3]-triazol-1-yl-trifluoroborates in 85-98% yields. This method was then developed into a facile one-pot synthesis for the preparation of various organo-[1,2,3]-triazol-1-yl-trifluoroborates using haloalkyltrifluoroborates as the starting materials.
Synthesis of Functionalized Organotrifluoroborates via Halomethyltrifluoroborates
摘要:
Potassium bromo- and iodomethyltrifluoroborates 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. Moreover, a new synthetic method for the preparation of potassium organotrifluoroborates through nucleophilic substitution of the halide in these potassium halomethyltrifluoroborates is described.
<sup>1</sup>
H, <sup>13</sup>
C, <sup>19</sup>
F and <sup>11</sup>
B NMR spectral reference data of some potassium organotrifluoroborates
作者:Roberta A. Oliveira、Ricardo O. Silva、Gary A. Molander、Paulo H. Menezes
DOI:10.1002/mrc.2467
日期:2009.10
Complete (1)H, (13)C, (19)F and (11)BNMRspectraldata for 28 potassiumorganotrifluoroborates are described. The resonance for the carbon bearing the boron atom is described for most of the studied compounds. A modified (11)BNMR pulse sequence was used and better resolution was observed allowing the observation of (11)B-(19)F coupling constants for some of the studied compounds.
A Palladium-Catalyzed Methylenation of Olefins Using Halomethylboronate Reagents
作者:Tim den Hartog、Juan Manuel Sarria Toro、Peter Chen
DOI:10.1021/ol403695b
日期:2014.2.21
Methylenation of electron-rich olefins is a highly challenging reaction, for which we have developed a new methodology exploiting Pd-catalysis and halomethylboronate reagents, the latter replacing diazomethane and zinc carbenoids as methylene donors. Optimization of the reaction for norbornene and extension to several other olefins are reported, with reasonable-to-excellent yields of cyclopropanes
A method of preparing a cyclopropane ring-bearing compound of the formula (I) in which R1 and R2 are independently selected from C1-C10 alky], optionally substituted, or R1 and R2 together with the bonds linking them to the cyclopropane ring, form a monocyclic or bicyciic ring system, which may comprise at least one hetero-atom, comprising the reaction of a compound of formula (II) in which R1 and R2 have the significances hereinabove defined, with a compound of formula (III) in which X is selected a nucieofuge selected from halides and pseudohalides and Y is an electro flige selected from boranes and borates, in the presence of a metal catalyst complex selected from those that a useful for catalytic cyclopropanation and those useful for catalyzing Heck coupling. The method prov ides a particularly easy and non-hazardous method of cyclopropanation.
Photoredox/Nickel Dual Catalytic Cross-Coupling of Potassium Thiomethyltrifluoroborates with Aryl and Heteroaryl Bromides
作者:Katherine Townsend、Malcolm P. Huestis、John C. Tellis
DOI:10.1021/acs.joc.1c00347
日期:2021.5.7
The cross-coupling of S-aryl and S-alkyl potassium thiomethyltrifluoroborates with aryl and heteroaryl bromides is reported via photoredox/nickel dual catalysis. The transformation is achieved under mild conditions with commercially available or readily prepared, air stable reagents and affords benzylthioether products in moderate to good yields with good functional group tolerance. A practical and
Direct Photoexcitable Iodomethylborate Enabling Cyclopropanation of Reactive Alkenes
作者:Rikako Nakamura、Yuto Sumida、Hirohisa Ohmiya
DOI:10.1246/bcsj.20220112
日期:2022.7.15
Radical-mediated cyclopropanation tool for reactive alkenes including dehydroamino acids (DHAAs) has been developed based on directly photoexcitable borate generating iodomethyl radical under visible light irradiation. The borate at the excited state serves as a strong single electron reductant. Therefore, this photoexcitable borate offers a simple protocol for cyclopropanation of DHAAs to forge m