Application of the Blaise reaction: stereoselective synthesis of (4R)-tert-butyl 3-amino-4-trimethylsilyloxy-2-alkenoates from (R)-cyanohydrins

Autor:	Franz Effenberger, Jana Syed, Siegfried Förster
Rok vydání:	1998
Předmět:	Aqueous solution Chemistry Organic Chemistry Diastereomer chemistry.chemical_element Zinc Catalysis Inorganic Chemistry chemistry.chemical_compound Reagent Organic chemistry Blaise reaction Stereoselectivity Physical and Theoretical Chemistry Racemization Dichloromethane
Zdroj:	Tetrahedron: Asymmetry. 9:805-815
ISSN:	0957-4166
DOI:	10.1016/s0957-4166(98)00039-1
Popis:	O-Trimethylsilyl protected (R)-cyanohydrins 3 react with Reformatsky reagents from tert-butyl 2-bromoesters 4 and zinc dust (Blaise reaction) to give the corresponding addition products in high yields. Workup with an aqueous solution of NH4Cl at low temperature gives (4R)-tert-butyl 3-amino-4-trimethylsilyloxy-2-alkenoates (R)-5 without racemization. Hydrogenation of the alkenoates 5 to the corresponding tert-butyl β-amino-γ-hydroxyalkanoates 6, resulting in a mixture of two diastereoisomers, was only possible under special hydrogenation conditions. With HCl in dichloromethane compounds 6 cyclize to the corresponding β-amino-γ-hydroxybutyrolactones 8.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::6b907eb84f24dc80f582dbd26cae163e https://doi.org/10.1016/s0957-4166(98)00039-1 Zobrazit plný text záznamu Full Text from ScienceDirect