Cleavage of 3-amino-o-carborane and its' N-derivatives by bases into the 3-amino-7,8-dicarbaundecaborate anion and its N-derivatives
摘要:
Cleavage of 3-amino-o-carborane by alcoholic alkali results in preferential elimination of the boron atom from position six of the polyhedron with the formation of a salt of 3-amino-7,8-dicarbaundecaborate and, to a smaller degree, to elimination of the boron bonded to the NH2 group, which leads to formation of a salt of 7,8-dicarbaundecaborate. Cleavage of 3-amino-o-carborane by piperidine is even more regioselective. Cleavage of N-derivatives of 3-amino-9-carborane by alcoholic alkali or piperidine is regiospecific, leading to salts of N-substituted 7,8-dicarbaundecaborates. 3-Ammonium-7,8-dicarbaundecaborate and a number of its N-derivatives were isolated in zwitterion form for the first time.
Catalytic Regioselective Cage B(8)–H Arylation of o-Carboranes via “Cage-Walking” Strategy
摘要:
A proof-of-concept example of catalytic regioselective cage B(8)-H functionalization of o-carboranes has been disclosed for the first time. Under the help of an acylamino directing group at cage B(3), a series of B(8)-arylated, B(4,7,8)-triarylated and B(4,7,8)-trifluorinated o-carborane derivatives were conveniently prepared. On the basis of isolation of a key intermediate, deuterium labeling experiments and DFT calculations, a reaction mechanism involving a high-valent palladium induced "cage-walking" from B(4) to B(8) vertex is proposed to account for the regioselective B(8)-H activation.
Preparative procedure for obtaining the secondary and tertiary amines of o-carborane [1,2-dicarbadodecaborane(12)] series by lithiumaluminumhydridereduction of their acyl derivatives has been worked out.
Visible-Light-Promoted Photocatalytic B−C Coupling via a Boron-Centered Carboranyl Radical: Facile Synthesis of B(3)-Arylated<i>o</i>-Carboranes
作者:Da Zhao、Zuowei Xie
DOI:10.1002/anie.201511251
日期:2016.2.24
A visible‐light‐mediated in situ generation of a boron‐centered carboranylradical (o‐C2B10H11.) has been described. With eosin Y as a photoredox catalyst, 3‐diazonium‐o‐carborane tetrafluoroborate [3‐N2‐o‐C2B10H11][BF4] was converted into the corresponding boron‐centered carboranylradical intermediate, which can undergo efficient electrophilic substitution reaction with a wide range of (hetero)arenes
[3-N<sub>2</sub>-o-C<sub>2</sub>B<sub>10</sub>H<sub>11</sub>][BF<sub>4</sub>]: a useful synthon for multiple cage boron functionalizations of o-carborane
作者:Da Zhao、Zuowei Xie
DOI:10.1039/c6sc01566b
日期:——
A simple and efficient method for selective cage B(3) multiple functionalization of o-carborane is described. Reaction of [3-N2-o-C2B10H11][BF4] with various kinds of nucleophiles gave a very broad spectrum of cage B(3)-substituted o-carborane derivatives, 3-X-o-C2B10H11 (X = OH, SCN, NH2, NO2, N3, CF3, PO(C6H5)2, etc). This reaction may serve as another efficient [18F]-radiolabeling method of carborane
描述了一种简单有效的邻碳硼烷选择性笼B(3)多官能化方法。 [3-N 2 - o -C 2 B 10 H 11 ][BF 4 ]与各种亲核试剂反应得到非常广谱的笼型B(3)-取代的邻碳硼烷衍生物,3-X- o - C 2 B 10 H 11 (X = OH、SCN、NH 2 、NO 2 、N 3 、CF 3 、PO(C 6 H 5 ) 2等)。该反应可以作为用于正电子发射断层扫描应用的碳硼烷簇的另一种有效的[ 18 F]-放射性标记方法。
Synthesis of carborane analogues of γ-aminobutanoic acid
作者:Valentina A. Ol’shevskaya、Rami Ayuob、Zhanna G. Brechko、Pavel V. Petrovskii、Elena G. Kononova、Galina L. Levit、Victor P. Krasnov、Valery N. Charushin、Oleg N. Chupakhin、Valery N. Kalinin
DOI:10.1016/j.jorganchem.2005.01.056
日期:2005.6
preparation of high yields of novel N-protected carborane amino acid derivatives, 3-acylamino-1-carboxymethyl-2-R-o-carboranes (R = H, Me, Ph), is reported. The synthesis starts from readily available 3-amino-o-carboranes and includes the protection of amino group, introduction of carboxymethyl function to the carbon atom of polyhedron via the metallation of carborane CH bond with sodium amide in liquid ammonia