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.
Three-Component Tandem-Intramolecular Hydroamination Reactions in One Pot Involving Indoles, 2-Aminobenzyl Alcohols, and 2-Alkynylbenzaldehydes: Consecutive 7-<i>endo</i>-<i>trig</i>and Electrophilic 6-<i>endo</i>-<i>dig</i>Cyclizations
作者:Srinivas Samala、Mohammad Saifuddin、Anil K. Mandadapu、Bijoy Kundu
DOI:10.1002/ejoc.201300100
日期:2013.6
A one-pot protocol for the synthesis of indole-based annulated polyheterocycles involvingconsecutive 7-endo-trig and electrophilic 6-endo-dig cyclizations is described. The reaction proceeds initially through annulation of 5-methoxyindole, 2-amino benzyl alcohol and 2-alkynylbenzaldehyde
Direct annulation and alkylation of indoles with 2-aminobenzyl alcohols catalyzed by TFA
作者:Forest J. Robertson、Bradshaw D. Kenimer、Jimmy Wu
DOI:10.1016/j.tet.2011.02.067
日期:2011.6
An efficient method for the annulation of indoles with 2-aminobenzyl alcohols, catalyzed by TFA, to furnish 5,6-fused indoline aminals is reported. This method can be extended to the alkylation of indoles at C3. 2-Aminobenzyl alcohols are used directly without recourse to protection of the aniline nitrogen or activation of the alcohol. (C) 2011 Elsevier Ltd. All rights reserved.