78782-27-1Relevant articles and documents
Reversible C?H Activation, Facile C?B/B?H Metathesis and Apparent Hydroboration Catalysis by a Dimethylxanthene-Based Frustrated Lewis Pair
Vasko, Petra,Zulkifly, Ili A.,Fuentes, M. ángeles,Mo, Zhenbo,Hicks, Jamie,Kamer, Paul C. J.,Aldridge, Simon
, p. 10531 - 10540 (2018)
A dimethylxanthene-based phosphine/borane frustrated Lewis pair (FLP) is shown to effect reversible C?H activation, cleaving phenylacetylene, PhCCH, to give an equilibrium mixture of the free FLP and phosphonium acetylide in CD2Cl2 solution at room temperature. This system also reacts with B?H bonds although in a different fashion: reactions with HBpin and HBcat proceed via C?B/B?H metathesis, leading to replacement of the -B(C6F5)2 Lewis acid component by -Bpin/-Bcat, and transfer of HB(C6F5)2 to the phosphine Lewis base. This transformation underpins the ability of the FLP to catalyze the hydroboration of alkynes by HBpin: the active species is derived from the HB(C6F5)2 fragment generated in this exchange process.
An “On-Demand”, Selective Dehydrogenative Borylation or Hydroboration of Terminal Alkynes Using Zn2+-based Catalyst
Bawari, Deependra,Dobrovetsky, Roman,Groutchik, Kristina,Jaiswal, Kuldeep
, (2022/03/18)
An air-stable dicationic Zn2+ complex (1) in a tripod-type ligand with non-bound phosphorus base and three pyridinyl “arms” (TPPh) was synthesized. Remarkably, while 2 mol% of 1 at room temperature selectively catalyzed dehydrogenative borylation of terminal alkynes with HBPin, a lower loading of 1 (0.5 mol%) at 90 °C selectively promoted hydroboration reaction of the same alkynes skipping the dehydrogenative borylation step. The mode of action of 1 was proposed based on experimental observations as well as the mechanism of dehydrogenative borylation was studied by DFT computations.
Pyridylpyrrolido ligand in Ge(ii) and Sn(ii) chemistry: Synthesis, reactivity and catalytic application
Pahar, Sanjukta,Sen, Sakya S.,Sharma, Vishal,Tothadi, Srinu
supporting information, p. 16678 - 16684 (2021/12/07)
In our previous communication, we have reported the synthesis of a new chlorogermylene (B) featuring a pyridylpyrrolido ligand. This study details the preparation of a series of new germylenes and stannylenes starting from B. A transmetallation reaction between B and SnCl2 led to the analogous chlorostannylene (1) with the simultaneous elimination of GeCl2. This is a very unusual example of transmetallation between two elements of the same group. The preparation of 1via lithiation led to the formation of 2 as a side product, where the ortho C-H bond of the pyridine ring was activated and functionalized with a nBu moiety. Subsequently, B and 1 were used as precursors to generate germylene (4) and stannylene (5) featuring tris(trimethylsilyl)silyl (hypersilyl) moieties. We also prepared tetrafluoropyridyl germylene (6) by reacting 4 with C5F5N with the simultaneous elimination of (Me3Si)3SiF by utilizing the fluoride affinity of the silicon atom. As there is scarcity of Sn(ii) compounds as single-site catalysts, we investigated 5 as a catalyst towards the hydroboration of aldehydes, ketones, alkenes and alkynes. All the compounds have been characterized by single-crystal X-ray diffraction and by state of the art spectroscopic studies.
Cu/Pd-catalyzed borocarbonylative trifunctionalization of alkynes and allenes: synthesis of β-geminal-diboryl ketones
Yuan, Yang,Wu, Fu-Peng,Spannenberg, Anke,Wu, Xiao-Feng
, p. 2142 - 2153 (2021/09/06)
Functionalized bisboryl compounds have recently emerged as a new class of synthetically useful building blocks in organic synthesis. Herein, we report an efficient strategy to synthesize β-geminal-diboryl ketones enabled by a Cu/Pd-catalyzed borocarbonylative trifunctionalization of readily available alkynes and allenes. This reaction promises to be a useful method for the synthesis of functionalized β-geminal-diboryl ketones with broad functional group tolerance. Mechanistic studies suggest that the reaction proceeds through borocarbonylation/hydroboration cascade of both alkynes and allenes. [Figure not available: see fulltext.]
