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Synfacts 2014; 10(5): 0546
DOI: 10.1055/s-0033-1341128
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

A Resin-Bound Phosphoric Acid Catalyst: Asymmetric Flow Reactions

Contributor(s):
Yasuhiro Uozumi
,
Yoichi M. A. Yamada
,
Aya Ohno
Osorio-Planes L, Rodríguez-Escrich C, Pericàs MA * Institute of Chemical Research of Catalonia, Tarragona and Universitat de Barcelona, Spain
Enantioselective Continuous-Flow Production of 3-Indolylmethanamines Mediated by an Immobilized Phosphoric Acid Catalyst.

Chem. Eur. J. 2014;
20: 2367-2372
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Further Information

Publication History

Publication Date:
17 April 2014 (online)

 
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Key words

chiral phosphoric acid - polystyrene - Friedel–Crafts reaction - continuous-flow synthesis

Significance

A polystyrene-supported chiral phosphoric acid promoted the enantioselective C3-alkylation of indoles 2 with sulfonylimines 1 to afford the 3-indolylmethanamines 3 in up to 94% yield with up to 98% ee (19 examples).


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Comment

The catalyst was reused thirteen times for the formation of 3a without significant loss of catalytic activity (13th reuse: 91% yield, 90% ee). The continuous-flow reaction using a catalyst-packed column was carried out for six hours to give 3a in 80% yield with 94% ee (TON = 102).


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