A bicyclo[3.1.1]heptano[4,3-c]pyrazole derived chiral auxiliary for dipolar cycloadditions

Autor:	Giorgio Molteni, Paola Del Buttero
Rok vydání:	2005
Předmět:	Chiral auxiliary Nitrile Bicyclic molecule Chemistry Stereochemistry Nitrilimine Organic Chemistry Pyrazole Catalysis Cycloaddition Inorganic Chemistry chemistry.chemical_compound Enantiopure drug Stereoselectivity Physical and Theoretical Chemistry
Zdroj:	Tetrahedron: Asymmetry. 16:1983-1987
ISSN:	0957-4166
DOI:	10.1016/j.tetasy.2005.04.014
Popis:	Starting form naturally occurring ( S )- cis -verbenol 1 and (1 R )-(−)-myrtenol 2 , we synthesised enantiopure bicyclo[3.1.1]heptano[4,3- c ]pyrazole derivatives 7 and 8 via a stereoselective nitrilimine cycloaddition as the key step. The effectiveness of the above skeleton as a new chiral auxiliary was evaluated towards the 1,3-dipolar cycloadditions of nitrile oxides and nitrilimines. Basic hydrolysis of the major cycloadducts gave enantiopure 5-carboxy-4,5-dihydroisoxazole ( S )-(+)- 19 and 5-carboxy-4,5-dihydropyrazole ( S )-(+)- 20 , respectively, which are of potential interest as chiral building blocks.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::f8e42c0137133007a1cd924f0dd793f2 https://doi.org/10.1016/j.tetasy.2005.04.014 Zobrazit plný text záznamu Full Text from ScienceDirect