The valuable tetrahydro-β- and γ-carboline skeleta can be accessed through Pictet-Spengler cyclisation initiated by acceptorless dehydrogenation of saturated cyclic amines. The substrate scope for the β-isomers is found to be somewhat limited, but access to the γ-isomers through the more reactive 2-(aminoethyl)indoles is more general. The synthetic utility of hydrogen transfer catalysis is highlighted in a two-step preparation of the alkaloid desbromoarborescidine A by sequential redox-neutral alkylation/dehydrogenative cyclisation.

中文翻译：

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通过无受体铱催化的叔胺脱氢氧化Pictet-Spengler环化反应

有价值的四氢-β-和γ-咔啉骨架可以通过Pictet-Spengler环化反应获得，该环化反应由饱和环胺的无受体脱氢反应引发。发现β-异构体的底物范围受到一定限制，但是通过反应性更强的2-（氨乙基）吲哚接近γ-异构体的途径更为普遍。通过顺序的氧化还原-中性烷基化/脱氢环化反应，生物碱去溴阿糖胞苷A的两步制备突出了氢转移催化的合成效用。