Rezayee Nomaan M, Lauridsen Vibeke H, Næsborg Line, Nguyen Thanh V Q, Tobiesen Henriette N, Jørgensen Karl Anker
Department of Chemistry , Aarhus University , DK-8000 Aarhus C , Denmark . Email:
Chem Sci. 2019 Feb 13;10(12):3586-3591. doi: 10.1039/c9sc00196d. eCollection 2019 Mar 28.
The first organocatalysed, metal-free cross-nucleophile coupling of indoles with α-branched aldehydes forming acyclic stereoselective quaternary carbon centres is presented. Applying an amino acid-derived catalyst with suitable organic oxidants affords the desired enantioenriched indole functionalised products with moderate to excellent yield and enantioselectivity. Two metal-free oxidative protocols employing either DDQ or a sequential approach that uses two organocatalysts to facilitate the use of O as the terminal oxidant are disclosed. These methods are compatible with various indoles ranging from electron-rich to -deficient substituents at the C-2, -5, -6, and -7-positions reacting with a series of different α-branched aldehydes.
首次报道了吲哚与α-支链醛的有机催化、无金属交叉亲核偶联反应，该反应形成了无环立体选择性季碳中心。使用氨基酸衍生的催化剂与合适的有机氧化剂，可得到所需的对映体富集的吲哚官能化产物，产率和对映选择性适中至优异。公开了两种无金属氧化方案，一种使用DDQ，另一种是采用顺序法，即使用两种有机催化剂以促进将氧气用作终端氧化剂。这些方法与各种吲哚兼容，这些吲哚在C-2、-5、-6和-7位具有从富电子到缺电子的取代基，可与一系列不同的α-支链醛发生反应。
