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Asymmetric Synthesis of Hydrocarbazoles Catalyzed by an Octahedral Chiral‐at‐Rhodium Lewis Acid |
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| Authors: | Yong Huang Liangliang Song Dr Lei Gong Prof?Dr Eric Meggers |
| Affiliation: | 1. Key Laboratory for Chemical Biology of Fujian Province and Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China;2. (+86)?0592‐2185821;3. Fachbereich Chemie, Philipps-Universit?t Marburg, Marburg, Germany |
| Abstract: | A bis‐cyclometalated chiral‐at‐metal rhodium complex catalyzes the Diels–Alder reaction between N‐Boc‐protected 3‐vinylindoles (Boc=tert‐butyloxycarbonyl) and β‐carboxylic ester‐substituted α,β‐unsaturated 2‐acyl imidazoles with good‐to‐excellent regioselectivity (up to 99:1) and excellent diastereoselectivity (>50:1 d.r.) as well as enantioselectivity (92–99 % ee) under optimized conditions. The rhodium catalyst serves as a chiral Lewis acid to activate the 2‐acyl imidazole dienophile by two‐point binding and overrules the preferred regioselectivity of the uncatalyzed reaction. |
| Keywords: | asymmetric catalysis chiral-at-metal Diels– Alder hydrocarbazoles rhodium |
