Organocatalytic Fischer Indolization Using the 2,2′-Biphenol/ B(OH)3 System
摘要:
An organocatalyzed Fischer indolization is established by combining 2,2′-biphenol (10 mol%) and B(OH)3 (30 mol%) as weak, readily available, and easy-to-handle acids. The inclusion of MgSO4, which efficiently scavenges NH3 (a possible acid catalyst poison), appears to be key to the success of this process. The corresponding indoles are obtained in yields of up to 91% using this method.y
Organocatalytic Fischer Indolization Using the 2,2′-Biphenol/ B(OH)3 System
摘要:
An organocatalyzed Fischer indolization is established by combining 2,2′-biphenol (10 mol%) and B(OH)3 (30 mol%) as weak, readily available, and easy-to-handle acids. The inclusion of MgSO4, which efficiently scavenges NH3 (a possible acid catalyst poison), appears to be key to the success of this process. The corresponding indoles are obtained in yields of up to 91% using this method.y
Reductive Hydrazination with Trichlorosilane: A Method for the Preparation of 1,1-Disubstituted Hydrazines
作者:Tao Wang、Xiao Di、Chao Wang、Li Zhou、Jian Sun
DOI:10.1021/acs.orglett.6b00675
日期:2016.4.15
and facile method has been developed to prepare 1,1-disubstituted hydrazines via Lewis base promoted direct reductive hydrazination. Under the catalysis of hexamethylphosphoramide (HMPA) and N,N-dimethylacetamide (DMAc), respectively, various ketones and aldehydes could react with phenylhdrazines to prepare 1,1-disubstituted hydrazines with good to high yields.
We present herein an unprecedented desymmetrization of meso 1,3-diones by enantioselective intermolecular condensation. Under the catalysis by a chiral phosphoric acid, a range of readily available 1,3-diones undergo reaction with hydrazines to produce cyclic and acyclic keto-hydrazones bearing an all-carbon quaternary center in high efficiency and enantioselectivity. These compounds are also highly