Palladium-Catalyzed Enantioselective C-3 Allylation of 3-Substituted-1H-Indoles Using Trialkylboranes
摘要:
We have developed a new enantioselective C-3 allylation of 3-substituted indoles using allyl alcohol and trialkylboranes. Asymmetric syntheses of 3,3-disubstituted indolines and indolenines in enantiomeric excesses up to 90% have been achieved using the bulky borane 9-BBN-C6H13 as the promoter of the reaction. The dependence of the selectivity on the nature of the borane suggests that the boron reagent has a role beyond promoting ionization of the allyl alcohol. A protocol for oxidation of indolenines to oxindoles has also been developed and led to a formal synthesis of (-)-phenserine.
Arylketones can be synthesized conveniently by a palladiumcatalyzedaddition of arylboronic acid to nitriles in aqueous triflic acid. This catalytic system was extended to the addition of unprotected indoles to nitriles under a slightly modified condition to produce 3-acyl indoles in good yields.
Facile Access to 3-Acylindoles through Palladium-Catalyzed Addition of Indoles to Nitriles: The One-Pot Synthesis of Indenoindolones
作者:Yuanhong Ma、Jingsong You、Feijie Song
DOI:10.1002/chem.201203354
日期:2013.1.21
The palladium‐catalyzed addition of indoles to nitriles affords 3‐acylindoles. The reaction proceeds with high selectivity, wide substrate scope, broadly available starting materials, and an operationally simple procedure. Combination with the palladium‐catalyzed intramolecular oxidative coupling of 3‐indolylarylketone gives access to indenoindolones in a one‐pot synthesis.
An efficient regioselective C-3 acylation of free indoles (N-H) has been accomplished via oxidative decarbethoxylation of easily available ethyl arylacetates using Cu(OAc)2 and KOtBu in DMSO.
Synthesis of 3-acylindoles via decarboxylative cross-coupling reaction of free (NH) indoles with α-oxocarboxylic acids
作者:Li-Jun Gu、Ji-Yan Liu、Li-Zhu Zhang、Yong Xiong、Rui Wang
DOI:10.1016/j.cclet.2013.10.004
日期:2014.1
Abstract A convenient and general method for acylation of free (N H) indoles via palladium-catalyzed decarboxylative cross-coupling reaction was developed. This process provided a useful method for the preparation of diverse 3-acylindoles in high yields utilizing a reaction with readily accessible reactants undermildconditions.
An efficient Cu-catalyzed decarboxylative C3-acylation of free (NâH) indoles using α-oxocarboxylic acids as acylating agents has been developed. This method was compatible with a variety of functional groups and provided an attractive alternative access to 3-acylindoles in moderate to high yields.