4250-48-0Relevant academic research and scientific papers
Synthesis of arylboronates by boron-induced ipso-deantimonation of triarylstibanes with boron trihalides and its application in one-pot two-step transmetallation/cross-coupling reactions
Yasuike, Shuji,Nakata, Kazuhide,Qin, Weiwei,Matsumura, Mio,Kakusawa, Naoki,Kurita, Jyoji
, p. 9 - 16 (2015/05/13)
The reaction of triarylstibanes (1) with boron trihalides (BCl3, and BBr3) afforded arylboron dihalides (2) by utilizing all the three aryl groups on the antimony. Boron intermediates (2) were transformed to arylboronates (3) in good to excellent yields by treatment with methanol and 1,3-propanediol. Further, the Pd-catalyzed reactions of 2 with organic halides such as 1-bromonaphthalene and benzoyl chloride in the presence of H2O afforded the corresponding cross-coupling products, unsymmetrical biaryls (4) and ketones (5), in moderate to good yields. The potential energy surfaces for the transmetallations of triarylstibanes (1) with BCl3 affording 2 were determined by molecular orbital calculations. The analyses of substituent effects on theoretically calculated reactivities showed the importance of the resonance effects of the ring substituents on these transmetallations.
Flash Vacuum Pyrolysis of o-Alkylaryl- and Arylalkylchloroboranes. - Synthesis of Benzoannulated Boracycloalkenes
Schacht, Wolfgang,Kaufmann, Dieter
, p. 1331 - 1338 (2007/10/02)
The dichloroorganylboranes chosen as pyrolytic starting materials were synthesized upon treatment of the corresponding triorganylboroxines and aryltrimethylsilanes (giving 3, 4) or the tetraorganylstannanes (giving 9-12, 17-20) with boron trichloride.At 700 deg C the flash vacuum pyrolysis of the dichloro(2-ethylphenyl)boranes 10 and 4 led to 1-boraindanes 21 and 22 selectively.The dichloro-2-tolylborane (9), the B-dimethylamino derivative, and mesitylboranes like 3 were completely stable upon pyrolysis.Pyrolyzing the isopropylphenylborane 12 1,5-elimination exclusively took place yielding 26, while pyrolysis of propylphenylborane 11 led to a mixture of boraindane 29 and boratetraline 30.To exclude such competitive reactions, some arylalkyldichloroboranes were pyrolyzed.At 750 deg C dichloro(2-methylbenzyl)borane (18) exclusively yielded oligomeric 2-chloro-2-boraindane (31).At 950 deg C even the pyrolysis of benzyldichloroborane (17) succeeded in a 1,4-elimination reaction yielding the eight-membered 2H-benzoborete dimer 34.The inversion barrier of 34 is ΔG(excit.)228 = 10.3 kcal mol-1, determined by NMR spectroscopy.The pyrolysis of the next-higher homologous dichloroorganylborane 19 yielded a boraindane 21 and a noncyclic diorganylborane 38 by a dehydroboration/hydroboration pathway.Both reaction types also took place when pyrolyzing dichloroborane (20): cyclization under formation of a five-membered ring system 39, formed upon attack of an aromatic C-H bond exclusively, and formation of an open-chain chlorodiorganylborane 40.
A New Borylation Method for Alkylbenzene and Polystyrene
Paetzold, Peter,Hoffmann, Juergen
, p. 3724 - 3733 (2007/10/02)
The borylation of alkylbenzenes by Hal2BH (Hal = F, Cl, Br) gives H2 and a mixture of m- and p-alkyl(dihaloboryl)benzenes.In the case of bulky alkyl groups, such as isopropyl, tert-butyl, these are partially split off as R - H and RBHal2.The phenyl groups in polystyrene-divinylbenzene copolymers undergo borylation with Br2BH in a 55percent yield.
Methyl group migration in the preparation of o-tolyl- and p-xylyldichloroboranes
Eggers,Kettle
, p. 1975 - 1977 (2007/10/16)
In the preparation of o-tolyldichloroborane and p-xylyldichloroborane migration of the methyl group ortho to the BCl2 group occurred. The evidence suggests that rearrangement occurs in a transition state in which the BCl2 group is only weakly bonded to the aromatic system.
