textjournal article
Regioselective Nitration and/or Halogenation of Iridabenzofurans through Electrophilic Substitution
Abstract
Regioselective electrophilic substitution reactions of the iridabenzofurans [Ir(C<sub>7</sub>H<sub>5</sub>O{OMe-7})(CO)(PPh<sub>3</sub>)<sub>2</sub>][OTf] (<b>1</b>) and IrCl(C<sub>7</sub>H<sub>5</sub>O{OMe-7})(PPh<sub>3</sub>)<sub>2</sub> (<b>2</b>) provide a convenient route to mononitro-, dinitro-, and mixed nitro-/halo-substituted derivatives. Treatment of cationic <b>1</b> with copper(II) nitrate in acetic anhydride (“Menke” nitration conditions) gives the mononitrated iridabenzofuran [Ir(C<sub>7</sub>H<sub>4</sub>O{NO<sub>2</sub>-2}{OMe-7})(CO)(PPh<sub>3</sub>)<sub>2</sub>][O<sub>3</sub>SCF<sub>3</sub>] (<b>3</b>). Under the same conditions neutral <b>2</b> undergoes dinitration to form IrCl(C<sub>7</sub>H<sub>3</sub>O{NO<sub>2</sub>-2}{NO<sub>2</sub>-6}{OMe-7})(PPh<sub>3</sub>)<sub>2</sub> (<b>5</b>). Simple substitution of the carbonyl ligand in <b>3</b> with chloride gives the neutral mononitro derivative IrCl(C<sub>7</sub>H<sub>4</sub>O{NO<sub>2</sub>-2}{OMe-7})(PPh<sub>3</sub>)<sub>2</sub> (<b>4</b>). Depending on the conditions employed, treatment of the iridabenzofurans <b>1</b> and <b>2</b> with Cu(NO<sub>3</sub>)<sub>2</sub> and either lithium chloride or lithium bromide in acetic anhydride gives either the mixed nitro-/halo-substituted iridabenzofurans IrCl(C<sub>7</sub>H<sub>3</sub>O{NO<sub>2</sub>-2}{Cl-6}{OMe-7})(PPh<sub>3</sub>)<sub>2</sub> (<b>6</b>) and IrCl(C<sub>7</sub>H<sub>2</sub>O{NO<sub>2</sub>-2}{NO<sub>2</sub>-4}{Cl-6}{OMe-7})(PPh<sub>3</sub>)<sub>2</sub> (<b>7</b>) or the simple halo-substituted iridabenzofurans [Ir(C<sub>7</sub>H<sub>4</sub>O{Cl-6}{OMe-7})(CO)(PPh<sub>3</sub>)<sub>2</sub>][OTf] (<b>8</b>), [Ir(C<sub>7</sub>H<sub>4</sub>O{Br-6}{OMe-7})(CO)(PPh<sub>3</sub>)<sub>2</sub>][OTf] (<b>9</b>), and IrBr(C<sub>7</sub>H<sub>3</sub>O{Br-2}{Br-6}{OMe-7})(PPh<sub>3</sub>)<sub>2</sub> (<b>10</b>). Bromination of <b>4</b> with pyridinium tribromide gives IrCl(C<sub>7</sub>H<sub>3</sub>O{NO<sub>2</sub>-2}{Br-6}{OMe-7})(PPh<sub>3</sub>)<sub>2</sub> (<b>11</b>). The molecular structures of <b>3</b>–<b>7</b> and <b>11</b> have been obtained by X-ray crystallography- Text
- Journal contribution
- Biophysics
- Microbiology
- Genetics
- Evolutionary Biology
- Ecology
- Immunology
- Infectious Diseases
- Computational Biology
- Environmental Sciences not elsewhere classified
- Biological Sciences not elsewhere classified
- Chemical Sciences not elsewhere classified
- Physical Sciences not elsewhere classified
- Electrophilic SubstitutionRegioselective electrophilic substitution reactions
- carbonyl ligand
- lithium chloride
- iridabenzofurans 1
- mononitrated iridabenzofuran
- cationic 1
- acetic anhydride
- IrCl
- pyridinium tribromide
- lithium bromide
- Regioselective Nitration
- Ir
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Last time updated on 12/02/2018
This paper was published in The Francis Crick Institute.
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