Asymmetric synthesis via iron acyl complexes
<p>This thesis describes the applications to asymmetric synthesis of the highly diastereoselective carbon-carbon bond forming reactions of α,β-unsaturated acyl ligands bound to the chiral iron auxiliary [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh&l...
Main Authors: | , |
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Other Authors: | |
Format: | Thesis |
Language: | English |
Published: |
1986
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Summary: | <p>This thesis describes the applications to asymmetric synthesis of the highly diastereoselective carbon-carbon bond forming reactions of α,β-unsaturated acyl ligands bound to the chiral iron auxiliary [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>)].</p><p> Chapter 1 briefly reviews the use of chiral auxiliaries in asymmetric synthesis.</p><p>Chapter 2 discusses the conformation of [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>)COCH<sub>3</sub>] with reference to its X-ray crystal structure. A method for determining the absolute configuration of (+)- and (-)-[(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>)COCH<sub>3</sub>] is described as well as methods for determining their optical purities.</p><p>Chapter 3 describes methods for the preparation of α,β-unsaturated acyl complexes. The Peterson reaction between the enolate derived from [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>) COCH<sub>2</sub> Si (CH<sub>3</sub>)<sub>3</sub>] and aldehydes gives complexes of the type [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>) COCH=CHR] as mixtures of E and Z isomers. Sodium hydride-induced elimination of methanol from either diastereoisomer of the corresponding β-methoxy acyl complex gives the E isomer stereo-selectively. Complexes of the type [η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>)COC(R)=CH<sub>2</sub>] are similarly prepared from the corresponding β-methoxy acyl complexes. The conformations of E- and Z- [η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>)COC(R)=CH<sub>2</sub>] are discussed with reference to the X-ray crystal structures of the β-methoxy substituted complexes.</p><p>See thesis pdf for remainder of abstract</p> |
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