The thiopyran route to polypropionates. Asymmetric synthesis of the building blocks by enantioselective protonation

Autor:	Jianheng Shen, Vishal Jheengut, Dale E. Ward, Idralyn Q. Alarcon, J. Wilson Quail, Olukayode T. Akinnusi
Rok vydání:	2004
Předmět:	Thiopyran Stereochemistry Organic Chemistry Enantioselective synthesis Protonation Catalysis Adduct Inorganic Chemistry chemistry.chemical_compound Aldol reaction chemistry Physical and Theoretical Chemistry Enantiomer Racemization
Zdroj:	Tetrahedron: Asymmetry. 15:2425-2430
ISSN:	0957-4166
DOI:	10.1016/j.tetasy.2004.06.027
Popis:	Enantioselective protonation of the s -BuLi derived lithium enolate of ( S )-phenyl 1,4-dioxa-8-thia-spiro[4.5]decane-6-carbothioate 14 with N -isopropylephedrine 15 gives 14 as a 10:1 mixture of enantiomers. Recrystallization of nonracemic 14 gives a highly enantioenriched material (>90% ee), which can be converted into 1,4-dioxa-8-thia-spiro[4.5]decane-6-carboxaldehyde 2 without racemization. Diastereoselective aldol reactions of tetrahydro-4 H -thiopyran-4-one with nonracemic 2 proceed with negligible racemization to give adducts that are useful building blocks for polypropionate synthesis.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7f5d81d0dd66e61f50e023cf5b2c9025 https://doi.org/10.1016/j.tetasy.2004.06.027 Zobrazit plný text záznamu Full Text from ScienceDirect