Stereoselective Synthesis of Lower and Upper Rim Functionalized Tetra-α Isomers of Calix[4]pyrroles.

Autor:	Díaz-Moscoso A; Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST) , Avda. Països Catalans 16, 43007 Tarragona, Spain., Hernández-Alonso D; Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST) , Avda. Països Catalans 16, 43007 Tarragona, Spain., Escobar L; Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST) , Avda. Països Catalans 16, 43007 Tarragona, Spain., Arroyave FA; Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST) , Avda. Països Catalans 16, 43007 Tarragona, Spain., Ballester P; Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST) , Avda. Països Catalans 16, 43007 Tarragona, Spain.; ICREA , Passeig Lluís Companys 23, 08010 Barcelona, Spain.
Jazyk:	angličtina
Zdroj:	Organic letters [Org Lett] 2017 Jan 06; Vol. 19 (1), pp. 226-229. Date of Electronic Publication: 2016 Dec 13.
DOI:	10.1021/acs.orglett.6b03505
Abstrakt:	Hydroxyaryl alkyl ketones with functionalized alkyl chains often fail to produce the corresponding tetra-α calix[4]pyrroles in Brönsted acid mediated condensations with pyrrole. A remarkable effect exerted by the addition of methyltrialkylammonium chloride during the acid-mediated syntheses of a series of meso-(tetrahydroxyaryl)-meso-tetraalkylcalix[4]pyrroles featuring alkyl terminal chloro or ester groups is reported. The ammonium salt enhances the cyclocondensation reaction and induces the almost exclusive formation of the tetra-α isomers.
Databáze:	MEDLINE
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