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.
An organocatalytic asymmetric vinylogousMichaeladdition of dicyanoolefins to vinylogousimineintermediatesgenerated in situfrom arenesulfonylalkylindoles has been developed. This protocol provides an easy and convenient approach to C-3 alkyl-substituted indole derivatives with high yields (up to 93%), diastereomeric ratios (up to 99:1 dr) and enantioselectivities (up to 99% ee). The resulting
A concise synthesis of spiro-cyclopropane compounds from indole derivatives and sulfur ylides has been developed via a dearomatization strategy. Moreover, the spiro-cyclopropane compounds could be conveniently transformed to rearomatized indole derivatives in the presence of acids.
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
Malononitrile on rare form: HighlyenantioselectiveMichaeladdition of malononitrile to vinylogousimineintermediates 2, generated in situfromarylsulfonylindoles 1, is described (see scheme). This protocol provides easy and convenient access to valuable 3‐indolyl derivatives 3 in high yields and enantioselectivities. A possible catalytic mechanism is proposed.