Biocatalytic asymmetric formation of tetrahydro-β-carbolines

Catalytic asymmetric synthesis of 1,1-disubstituted tetrahydro-β-carbolines by phase-transfer catalyzed alkylations.

Efficient catalytic asymmetric synthesis of 1,1-disubstituted tetrahydro-β-carbolines has been achieved via asymmetric alkylation of 1-cyanotetrahydro-β-carbolines using a binaphthyl-modified N-spiro-type chiral phase-transfer catalyst. This is a valuable example of hitherto difficult highly enantioselective alkylations at α-carbon of the cyano group under phase-transfer conditions.

Asymmetric synthesis of tetrahydro-β-carbolines via chiral phosphoric acid catalyzed transfer hydrogenation reaction.

Chiral phosphoric acid catalyzed enantioselective transfer hydrogenation of hydroxylactams has been realized to provide enantioenriched tetrahydro-β-carbolines in dioxane at room temperature (up to 94% yield, 90% ee).

Pharmacological importance of optically active tetrahydro-β-carbolines and synthetic approaches to create the C1 stereocenter.

1,2,3,4-Tetrahydro-β-carbolines (THβCs) are a pharmacologically important group of compounds belonging to the indole alkaloids. C1-Substituted optically active THβCs have been the target of extensive synthetic efforts due to the presence of the scaffold in numerous natural products and synthetic targets. This review briefly summarizes the methods to obtain the C1 stereocenter and concentrates o...

Synthesis of tetrahydro-β-carbolines via isomerization of N-allyltryptamines: a metal-catalyzed variation on the Pictet-Spengler theme.

An efficient and broadly applicable alternative to the classical Pictet-Spengler synthesis of tetrahydro-β-carbolines is presented. The method relies on metal-catalyzed isomerization of allylic amines to form reactive iminium intermediates which can be trapped by a tethered indole nucleophile.

Formal asymmetric biocatalytic reductive amination.