3 research outputs found
Enantioselective Synthesis of an All-Carbon Quaternary Stereocenter by Chiral BrĂžnsted Acid-Catalyzed FriedelâCrafts-Type Reaction between Pyrroles and 3âIndolylmethanols
We have developed a chiral phosphoric acid-catalyzed
enantioselective
FriedelâCrafts alkylation reaction between pyrroles and indolylmethanols.
Wide substrate scope was observed, and a chiral all-carbon quaternary
center was constructed at the 3 position of indoles in high yields
with high to excellent enantioselectivities (up to 99% ee)
Îș<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)âAllylphosphane Iridium(III) and Rhodium(III) Complexes: Preparation and Reactivity toward Nucleophilic Reagents
The
first allylphosphane iridium complexes [IrCl<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{ÎșÂ(<i>P</i>)-R<sub>2</sub>PCH<sub>2</sub>CHî»CH<sub>2</sub>}] (R = <i>i</i>Pr (<b>1a</b>), Ph (<b>1b</b>)) have been synthesized
by the reaction of the dimeric complex [IrClÂ(ÎŒ-Cl)Â(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)]<sub>2</sub> with allyldiisopropylphosphane
(ADIP) and allyldiphenylphosphane (ADPP), respectively. The cationic
complex [IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHî»CH<sub>2</sub>}]<sup>+</sup> (<b>3</b><sup><b>+</b></sup>) has been prepared
by the reaction of complex <b>1a</b> with NaX (X = BPh<sub>4</sub>, PF<sub>6</sub>) in dichloromethane. The complex <b>3<sup>+</sup></b> reacts with phosphanes and alkanethiolates to give the uncommon
cationic complexes [IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>2</sup>(<i>P</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHÂ(PR<sub>2</sub>RâČ)ÂCH<sub>2</sub>}]<sup>+</sup> (<b>5</b><sup><b>+</b></sup>â<b>7</b><sup>+</sup>) and IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>3</sup>(<i>P</i>,<i>C,S</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHÂ(SR)ÂCH<sub>2</sub>}]<sup>+</sup> (<b>13</b><sup><b>+</b></sup> and <b>14</b><sup><b>+</b></sup>) by chemo- and regioselective
addition of the nucleophiles to the Ï-olefin system. The reaction
of <b>1a</b> with LiBHEt<sub>3</sub> gives the neutral complex
[IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>2</sup>(<i>P</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>}] (<b>10</b>). For comparative purposes, the synthesis of the complex
[RhClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHî»CH<sub>2</sub>}]<sup>+</sup> (<b>4</b><sup><b>+</b></sup>) and its reactivity
with phosphanes, hydride, and thiolates has been also assayed
Îș<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)âAllylphosphane Iridium(III) and Rhodium(III) Complexes: Preparation and Reactivity toward Nucleophilic Reagents
The
first allylphosphane iridium complexes [IrCl<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{ÎșÂ(<i>P</i>)-R<sub>2</sub>PCH<sub>2</sub>CHî»CH<sub>2</sub>}] (R = <i>i</i>Pr (<b>1a</b>), Ph (<b>1b</b>)) have been synthesized
by the reaction of the dimeric complex [IrClÂ(ÎŒ-Cl)Â(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)]<sub>2</sub> with allyldiisopropylphosphane
(ADIP) and allyldiphenylphosphane (ADPP), respectively. The cationic
complex [IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHî»CH<sub>2</sub>}]<sup>+</sup> (<b>3</b><sup><b>+</b></sup>) has been prepared
by the reaction of complex <b>1a</b> with NaX (X = BPh<sub>4</sub>, PF<sub>6</sub>) in dichloromethane. The complex <b>3<sup>+</sup></b> reacts with phosphanes and alkanethiolates to give the uncommon
cationic complexes [IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>2</sup>(<i>P</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHÂ(PR<sub>2</sub>RâČ)ÂCH<sub>2</sub>}]<sup>+</sup> (<b>5</b><sup><b>+</b></sup>â<b>7</b><sup>+</sup>) and IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>3</sup>(<i>P</i>,<i>C,S</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHÂ(SR)ÂCH<sub>2</sub>}]<sup>+</sup> (<b>13</b><sup><b>+</b></sup> and <b>14</b><sup><b>+</b></sup>) by chemo- and regioselective
addition of the nucleophiles to the Ï-olefin system. The reaction
of <b>1a</b> with LiBHEt<sub>3</sub> gives the neutral complex
[IrClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>2</sup>(<i>P</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>}] (<b>10</b>). For comparative purposes, the synthesis of the complex
[RhClÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â{Îș<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)-<i>i</i>Pr<sub>2</sub>PCH<sub>2</sub>CHî»CH<sub>2</sub>}]<sup>+</sup> (<b>4</b><sup><b>+</b></sup>) and its reactivity
with phosphanes, hydride, and thiolates has been also assayed