ChemInform Abstract: Pauson—Khand Approach to Chiral, Diastereomerically Pure Group 4 ansa-Metallocene Complexes.
✍ Scribed by Robert B. Grossman
- Publisher
- John Wiley and Sons
- Year
- 2010
- Weight
- 34 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0931-7597
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✦ Synopsis
Pauson-Khand Approach to Chiral, Diastereomerically Pure Group 4 ansa-Metallocene Complexes.
-Dienediynes (IIIa) and (IIIb), readily prepared from tosylates (I) by alkylation with lithioalkynes (II), are converted to diastereopure Pauson-Khand (P-K) products (V) by reaction with Co 2 (CO) 8 , whereas compound (IIIc) fails to react under P-K conditions. Only the phenyl derivative (Va) is successfully transformed to the desired cyclopentadienyl derivative (VIII). The elimination reaction of the tert-butyl analogue of compound (VII) leads to an undesired tetraene which cannot be converted to a cyclopentadienyl derivative. All attempts to add compound (VIII) to ZrCl 4 or TiCl 3 to provide metallocene complexes fail. -(GROSSMAN, ROBERT