Enantioselective Michael Addition of 1,3-Diketones to Arenesulfonylalkylindoles: A Flexible Gateway to Optically Active 3-sec-Alkyl-Substituted Indoles Containing a Pyrazole Skeleton
4-positions, without decrease of the enantioselectivity. EnantioselectiveMichaeladdition of 1,3-diketones to alkylideneindolenines generated in situfrom arenesulfonylalkylindoles is described, and a series of optically active C3-alkyl-substituted indole derivatives has been obtained. The resulting adducts can be readily converted into 3-sec-alkyl-substituted indoles containing a pyrazole skeleton, with
Organocatalytic Asymmetric Michael Addition of Oxazolones to Arylsulfonyl Indoles: Facile Access to<i>syn</i>-Configured α,β-Disubstituted Tryptophan Derivatives
Enantioselective Michaeladdition of oxazolones to in situ generated vinylogous imine intermediates is reported. A series of optically active 3-alkylindole derivatives with adjacent quaternary and tertiary stereocenters was obtained. The resulting adducts can readily be converted into syn-configured α,β-disubstitutedtryptophanderivatives without compromising the stereoselectivities.
The rhodium-catalyzed addition of arylboronic acids to vinylogous imines generated in situ from sulfonylindoles has been developed. This procedure provided a rapid approach to C-3 sec-alkyl-substituted indoles.
A convenient approach to 3-sec-alkyl substituted indoles was developed via palladium-catalyzed addition of arylboronic acids to vinylogousiminesgenerated in situfrom sulfonylindoles under mild conditions.
Catalytic asymmetric coupling of vinylogous species <i>via</i> deconjugated butenolide addition to vinylogous imines <i>in situ</i> generated from arylsulfonyl indoles
An efficient catalytic asymmetric coupling of vinylogous species is developed via deconjugated butenolide addition to vinylogousimines in situgeneratedfromarylsulfonylindoles. With quinine-derived bifunctional squaramide as the catalyst, a series of structurally diverse enantioenriched sec-alkyl-3-substituted indoles containing valuable γ,γ-disubstituted butenolide moieties and adjacent quaternary-tertiary