Catalytic and highly enantioselective Friedel–Crafts type reactions of heteroaromatic compounds with trifluoropyruvate and glyoxylate by a dicationic palladium complex
摘要:
The highly enantioselective Friedel-Crafts alkylation of furan and thiophene derivatives with trifluoropyruvate, which have never provided the high level of asymmetric induction and yield until now, was achieved by using dicationic palladium complexes as Lewis acid catalysts. Moreover, glyoxylate instead of trifluoropyruvate as an electrophile led to complete change of regioselectivity with 2-trimethylsilylated furan, thiophene, and pyrrole derivatives to give the corresponding heteroarylated products in high yields and enantioselectivities. The respective products with trifluoropyruvate and glyoxylate could also be obtained via sequential catalytic reaction; intramolecular cyclization of alkynyldiols using cationic Au catalyst followed by Friedel-Crafts type reactions using dicationic Pd catalyst. (C) 2014 Elsevier Ltd. All rights reserved.
Asymmetric carbonyl-ene and Friedel–Crafts reactions catalysed by Lewis acid platinum group metal complexes of the enantiopure atropisomeric biaryl-like diphosphine (S)-Me2-CATPHOS: a comparison with BINAP
作者:Simon Doherty、Julian G. Knight、Hamid Mehdi-Zodeh
DOI:10.1016/j.tetasy.2012.01.022
日期:2012.2
Lewis acid platinum and palladium complexes of (S)-Me-2-CATPHOS catalyse the carbonyl-ene reaction between allylbenzene derivatives and ethyl trifluoropyruvate to give the expected alpha-hydroxy esters with ee's up to 97%, while the corresponding reaction involving 2-allylfuran and thiophene was exclusively selective for Friedel-Crafts-type reactivity and gave the corresponding 2-hydroxy-trifluoromethyl ethyl esters in good yield and moderate to good enantioselectivity. (C) 2012 Elsevier Ltd. All rights reserved.
WO2007/38444
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WO2008/48540
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Catalytic and highly enantioselective Friedel–Crafts type reactions of heteroaromatic compounds with trifluoropyruvate and glyoxylate by a dicationic palladium complex
The highly enantioselective Friedel-Crafts alkylation of furan and thiophene derivatives with trifluoropyruvate, which have never provided the high level of asymmetric induction and yield until now, was achieved by using dicationic palladium complexes as Lewis acid catalysts. Moreover, glyoxylate instead of trifluoropyruvate as an electrophile led to complete change of regioselectivity with 2-trimethylsilylated furan, thiophene, and pyrrole derivatives to give the corresponding heteroarylated products in high yields and enantioselectivities. The respective products with trifluoropyruvate and glyoxylate could also be obtained via sequential catalytic reaction; intramolecular cyclization of alkynyldiols using cationic Au catalyst followed by Friedel-Crafts type reactions using dicationic Pd catalyst. (C) 2014 Elsevier Ltd. All rights reserved.