Glycosylidene Carbenes. Part 4. Synthesis of Spirocyclopropanes from Acetamidoglycosylidene-Derived Diazirines

Autor:	Andrea Vasella, Christian Witzig, René Husi
Rok vydání:	1991
Předmět:	chemistry.chemical_classification Bicyclic molecule Nitrile Stereochemistry Organic Chemistry Oxime Biochemistry Catalysis Inorganic Chemistry chemistry.chemical_compound chemistry Drug Discovery Diazirine Solvolysis Physical and Theoretical Chemistry Allyl alcohol Acrylonitrile Lactone
Zdroj:	Helvetica Chimica Acta. 74:1362-1372
ISSN:	1522-2675 0018-019X
DOI:	10.1002/hlca.19910740625
Popis:	The synthesis of the first glycosylidene-derived 2-acetamido-2-deoxydiazirine 4 from N-acetylglucosamine 6 is described. Thus, 6 was transformed into the 3-O-mesylglucopyranoside 9 by glycosidation with allyl alcohol, benzylidenation, and mesylation (Scheme 2). Solvolysis of 9 gave the allopyranoside 10 which, upon benzylation and glycoside cleavage, yielded the hemiacetals 12. Using our established method (via the lactone oxime 14 and the diaziridines 16), 12 gave the diazirine 4. Thermolysis of this diazirine in the presence of i-PrOH gave the dihydro-1,3-oxazole 5 (Scheme 1); in the presence of acrylonitrile, the four diastereoisomeric spirocyclopropanes 17–20 and the acetamidoallal 21 were obtained and separated by prep. HPLC (Scheme 3). Assignment of the configuration of 17–20 is based on NOE measurements and on the effect of diamagnetic anisotropy of the CN group. The ratio of the four cyclopropanes, which is in keeping with earlier results, is rationalized.
Databáze:	OpenAIRE
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