Preparation of [closo-CB11H12]- by Dichlorocarbene Insertion Into [nido-B11H14]-

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Title:Preparation of [closo-CB11H12]- by Dichlorocarbene Insertion Into [nido-B11H14]-
Creators:
Franken, Andreas
King, Benjamin T.
Rudolph, Jens
Rao, Photon
Noll, Bruce C.
Michl, Josef
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 66, 8, pp. 1238-1249
Uncontrolled Keywords:Dihalocarbenes, Boranes, Haloforms, [<i>closo</i>-CB<sub>11</sub>H<sub>12</sub>]<sup>-</sup> anion, Carboranes

Abstract

In strongly basic media, the [<i>nido</i>-B<sub>11</sub>H<sub>14</sub>]<sup>-</sup> anion reacts with the haloforms. Dehydrogenation to [<i>closo</i>-B<sub>11</sub>H<sub>11</sub>]<sup>2-</sup> is the only reaction observed with iodoform. With chloroform and bromoform, the cage is expanded by dihalocarbene insertion. The dominant products are the [<i>closo</i>-CB<sub>11</sub>H<sub>12</sub>]<sup>-</sup> and the [2-Br-<i>closo</i>-CB<sub>11</sub>H<sub>12</sub>]<sup>-</sup> anion, respectively. The chief side product is the [<i>closo</i>-B<sub>11</sub>H<sub>11</sub>]<sup>2-</sup> anion, which results from dehydrogenation of the starting material. It was identified by <sup>11</sup>B NMR spectroscopy and isolated after acidic aqueous workup in the form of the [<i>nido</i>-7-OH-B<sub>11</sub>H<sub>13</sub>]<sup>-</sup> anion. Since the starting [<i>nido</i>-B<sub>11</sub>H<sub>14</sub>]<sup>-</sup> anion is available from NaBH<sub>4</sub> and BF<sub>3</sub>·Et<sub>2</sub>O in 50% yield, its conversion to [<i>closo</i>-CB<sub>11</sub>H<sub>12</sub>]<sup>-</sup> with chloroform and base in a 40% yield represents a useful laboratory route to the numerous known but previously very expensive derivatives of [<i>closo</i>-CB<sub>11</sub>H<sub>12</sub>]<sup>-</sup>, highly prized for their very low nucleophilicity. <p>

Title:Preparation of [closo-CB11H12]- by Dichlorocarbene Insertion Into [nido-B11H14]-
Creators:
Franken, Andreas
King, Benjamin T.
Rudolph, Jens
Rao, Photon
Noll, Bruce C.
Michl, Josef
Uncontrolled Keywords:Dihalocarbenes, Boranes, Haloforms, [<i>closo</i>-CB<sub>11</sub>H<sub>12</sub>]<sup>-</sup> anion, Carboranes
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:66
Number:8
Page Range:pp. 1238-1249
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20011238UNSPECIFIED
ID Code:1853
Item Type:Article
Deposited On:06 Feb 2009 17:13
Last Modified:06 Feb 2009 16:13

Citation

Franken, Andreas; King, Benjamin T.; Rudolph, Jens; Rao, Photon; Noll, Bruce C.; Michl, Josef (2001) Preparation of [closo-CB11H12]- by Dichlorocarbene Insertion Into [nido-B11H14]-. Collection of Czechoslovak Chemical Communications, 66 (8). pp. 1238-1249. ISSN 0010-0765

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