The first atroposelective synthesis
of pyrrolo[3,4-b]pyridines catalyzed by N-heterocyclic carbene has
been achieved. A wide range of chiral atropisomers of pyrrolo[3,4-b]pyridines were obtained in high yields with excellent
enantioselectivities (96–99% enantiomeric excess). The experimental
results and density functional theory calculations showed that the
C–N axial chirality of the product had high thermal stability.
An efficient and practical method for the synthesis of indolyl-nitroalkane derivatives catalyzed by N-bromosuccinimide is described. The generality of this method was demonstrated by synthesizing an array of diverse 3-substituted indole derivatives by the reaction of different β-nitrostyrenes with various substituted indoles. Simple reaction conditions accompanied by good yields of indolyl-nitroalkanes are the merits of this methodology.
Optically enriched cyclopentenones are synthetically versatile molecules, and their rapid and efficient straightforward assembly from simple starting materials is highly desired. Herein, we report a rhodium‐catalyzed enantioselective formal [4+1] cycloaddition of diazooxindoles and the Danishefsky diene. The formation of cyclopentenones proceeds via ring expansion of the vinylcyclopropanes formed in situ via cyclopropanation. The optically and highly structurally enriched indoline spirocyclopentenone bearing an all‐carbon stereocenter was formed in a one‐pot, two‐step manner in good to excellent yields and enantioselectivities (up to 90 % ee).
The first N-heterocyclic carbene-catalyzed enantioselective dearomatizing annulation of benzoxazoles with α,β-unsaturated aldehydes has been achieved. The reaction was found to be compatible with a wide range of benzoxazoles and the...
Rodium chiral diene complex-catalyzed enantioselective cycloaddition of aryl α-diazoarylacetates and electron-enriched Danishefsky-type dienes afforded highly functionalized and optically enriched cyclopentenones in excellent yields (up to 97% yield) and with good to excellent enantioselectivities (60-92% ee). (-)-1,13-Herbertenediol was successfully synthesized in an overall 25% yield employing the optically enriched cyclopentenone with an all-carbon quaternary center as the key intermediate.
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