Proton-Sponge-Initiated Reactions of 6,8-Dicarba-arachno-nonaborane(13) and 6,7-Dicarba-arachno-nonaborane(13) with Methyl Propynoate: One-Step Syntheses of the 6-(MeOOCCH2)-5,6,7-Tricarba-arachno-decaborane(12) and 6-(MeOOCCH2)-5,6,10-Tricarba-nido-decaborane(10) Tricarbaboranes

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Title:Proton-Sponge-Initiated Reactions of 6,8-Dicarba-arachno-nonaborane(13) and 6,7-Dicarba-arachno-nonaborane(13) with Methyl Propynoate: One-Step Syntheses of the 6-(MeOOCCH2)-5,6,7-Tricarba-arachno-decaborane(12) and 6-(MeOOCCH2)-5,6,10-Tricarba-nido-decaborane(10) Tricarbaboranes
Creators:
Wille, Andrew E.
Sneddon, Larry G.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 62, 8, pp. 1214-1228
Uncontrolled Keywords:<i>ab initio</i>/IGLO calculations, Carborane, Tricarbaborane, Carbon insertion

Abstract

The reaction of arachno-6,8-C<sub>2</sub>B<sub>7</sub>H<sub>13</sub> (<strong>1</strong>) with methyl propynoate in the presence of only 0.1 equivalent of 1,8-bis(dimethylamino)naphthalene (Proton Sponge&reg;, PS) results in the one-step formation of the neutral tricarbaborane 6-(MeOOCCH<sub>2</sub>)-<i>arachno</i>-5,6,7-C<sub>3</sub>B<sub>7</sub>H<sub>12 </sub>(<strong>2</strong>). Similarly, only 0.1 equivalent of PS initiates the reaction of the isomeric <i>arachno</i>-6,7-C<sub>2</sub>B<sub>7</sub>H<sub>13 </sub>(<strong>3</strong>) carborane with methyl propynoate to yield the new tricarbaborane, 6-(MeOOCCH<sub>2</sub>)-<i>nido</i>-5,6,10-C<sub>3</sub>B<sub>7</sub>H<sub>10 </sub>(<strong>4</strong>). These results suggest a cyclic reaction sequence involving initial deprotonation of the starting dicarbaborane by PS, followed by reaction of the resulting anion with methyl propynoate to produce a new anion. Protonation of this second anion by another equivalent of the starting dicarbaborane then produces the final neutral tricarbaborane product and the cycle begins again. While <strong>4</strong> is unreactive toward NaH or KH, it readily added <i>n</i>-BuLi to give, following acidification with HCl-Et<sub>2</sub>O, a new product tentatively identified as 6-(MeOOCCH<sub>2</sub>)-Bu-<i>arachno</i>-5,6,10-C<sub>3</sub>B<sub>7</sub>H<sub>11 </sub>(<strong>6</strong>). The proposed structures of <strong>4</strong> and <strong>6</strong> are strongly supported by <i>ab initio</i>/IGLO nuclear shielding calculations.

Title:Proton-Sponge-Initiated Reactions of 6,8-Dicarba-arachno-nonaborane(13) and 6,7-Dicarba-arachno-nonaborane(13) with Methyl Propynoate: One-Step Syntheses of the 6-(MeOOCCH2)-5,6,7-Tricarba-arachno-decaborane(12) and 6-(MeOOCCH2)-5,6,10-Tricarba-nido-decaborane(10) Tricarbaboranes
Creators:
Wille, Andrew E.
Sneddon, Larry G.
Uncontrolled Keywords:<i>ab initio</i>/IGLO calculations, Carborane, Tricarbaborane, Carbon insertion
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:62
Number:8
Page Range:pp. 1214-1228
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19971214UNSPECIFIED
ID Code:1201
Item Type:Article
Deposited On:06 Feb 2009 17:07
Last Modified:06 Feb 2009 16:07

Citation

Wille, Andrew E.; Sneddon, Larry G. (1997) Proton-Sponge-Initiated Reactions of 6,8-Dicarba-arachno-nonaborane(13) and 6,7-Dicarba-arachno-nonaborane(13) with Methyl Propynoate: One-Step Syntheses of the 6-(MeOOCCH2)-5,6,7-Tricarba-arachno-decaborane(12) and 6-(MeOOCCH2)-5,6,10-Tricarba-nido-decaborane(10) Tricarbaboranes. Collection of Czechoslovak Chemical Communications, 62 (8). pp. 1214-1228. ISSN 0010-0765

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