✦ LIBER ✦
Stereocontrolled synthesis of R or S E or Z unsaturated α—amino acids by enantio- and diastereoselective epoxidation of δ-hydroxy allylic phosphine oxides
✍ Scribed by Jonathan Clayden; Eric W. Collington; Stuart Warren
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- French
- Weight
- 271 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Epoxidadon of Shydroxy allylic phosphinc oxides 5 with m-CPBA can be syn selective. All srereoisomers of epoxy alcohols 6 are available when this melhod is used in tandem with an anti selective Sharpless kinetic resolution. The stereoisomers of epoxy alcohols 6 can be Iraqformed stereospec#iially inw singk isomers of utmumed a-atnk acids 7. A mechanistic explanation for the stereoselectivity observed in the m-CPBA epoxidadon is proposed.
We are currently making use of the epoxides 2 of allylic phosphine oxides 1 as regio-and stereocontrolled ally1 cation equivalents. 1 Nucleophilic opening of the epoxide, followed by Homer-Wittig