1,2-Induction in intramolecular diene cyclozirconation: Control of relative configuration
β Scribed by Douglass F. Taber; James P. Louey
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- French
- Weight
- 594 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0040-4020
No coin nor oath required. For personal study only.
π SIMILAR VOLUMES
Chiral, double-activated enophiles in 1,7-dienes 6a -d undergo thermal and Lewis-acid catalyzed intramolecular ene reactions yielding trans-cyclohexanes 7a-d and 8a-d.
The effects of varying the activating groups in the enophile and of geminal substitution in the connecting chain on the rates and stereoselectivities of the title reactions have been investigated.
Depending on the reducing agent and reaction conditions, diastereoselective reduction of 3-[3-(4Π-bromo[1,1Π-biphenyl]-4-yl)-3-keto-1-phenylpropyl]-4hydroxy-2H-1-benzopyran-2-one (2) proceeds with different stereoselectivity; a surprisingly high, approximately 90% d.e. of 4A is achieved with NaBH 4
## Cyclic hydroboration of an appropriately substituted 1.5~diene yields a 1,5 dial as the major product which can be converted to the racemic Prelog-Djerassi lactone. The widespread occurrence of the three carbon unit 1 in natural products of current synthetic interest has prompted us to investig