Enantioenriched tetrahydro-/?-carbolines

A synthesis of enantioenriched tetrahydro- -carbolines has been reported using chiral phosphoric acid in conjunction with Hoveyda-Grubbs II catalyst through a ring-closing metathesis/isomerization/Pictet-Spengler cascade reaction (Scheme 93). ... 

Wang et al. have developed an efficient SPINOL-phosphoric acid (160) catalysed asymmetric Pictet-Spengler reaction of a-naphthylmethyl ttyptamines (158) with a wide range of aliphatic and aromatic aldehydes, affording a series of highly enantioenriched tetrahydro-) -carboline derivatives (159) (Scheme 57)7 ... 

Table 6.6 Asymmetric synthesis of enantioenriched tetrahydro-p-carbolines 64 reported by You.

On the basis of the above mechanistic studies, the You group designed an Ir-catalyzed tandem dearomatization/migration protocol for asymmetric synthesis of enantioenriched tetrahydro-p-carboline derivatives 190 (Table 6.16). The migratory group in this reaction is methylene adjacent... 

A catalytic as5mmetric Pictet-Spengler reaction has been developed. This process furnishes enantioenriched tetrahydro-P-carbolines (88) from various tryptamines and both aromatic and aliphatic aldehydes if treated with chiral Bronsted acid catalyst (89) (Scheme 25). ... 

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