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  • Gold and BINOL-phosphoric acid catalyzed enantioselective hydroamination/N-sulfonyliminium cyclization cascade.

Gold and BINOL-phosphoric acid catalyzed enantioselective hydroamination/N-sulfonyliminium cyclization cascade.

Organic letters (2013-08-30)
Alex W Gregory, Pavol Jakubec, Paul Turner, Darren J Dixon
PMID23985045
ABSTRACT

A highly enantioselective hydroamination/N-sulfonyliminium cyclization cascade is reported using a combination of gold(I) and chiral phosphoric acid catalysts. An initial 5-exo-dig hydroamination and a subsequent phosphoric acid catalyzed cyclization process provide access to complex sulfonamide scaffolds in excellent yield and high enantiocontrol. The method can be extended to lactam derivatives, with excellent yields and enantiomeric excesses of up to 93% ee.

MATERIALS
Product Number
Brand
Product Description
466123
Sigma-Aldrich
Phosphoric acid, crystalline, ≥99.999% trace metals basis
345245
Sigma-Aldrich
Phosphoric acid, 85 wt. % in H2O, 99.99% trace metals basis
452289
Sigma-Aldrich
Phosphoric acid, ≥85 wt. % in H2O, ≥99.999% trace metals basis
P5811
Sigma-Aldrich
Phosphoric acid, BioReagent, suitable for insect cell culture, 85%
79617
Sigma-Aldrich
Phosphoric acid, BioUltra, ≥85% (T)
30417
Sigma-Aldrich
Phosphoric acid, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥85%
695017
Sigma-Aldrich
Phosphoric acid, ACS reagent, ≥85 wt. % in H2O
04107
Sigma-Aldrich
Phosphoric acid, puriss., meets analytical specification of Ph. Eur., BP, NF, FCC, 85.0-88.0%
79622
Sigma-Aldrich
Phosphoric acid, puriss. p.a., crystallized, ≥99.0% (T)
438081
Sigma-Aldrich
Phosphoric acid, ACS reagent, ≥85 wt. % in H2O