Catalyst-Free Dehydrative α-Alkylation of Ketones with Alcohols: Green and Selective Autocatalyzed Synthesis of Alcohols and Ketones
作者:Qing Xu、Jianhui Chen、Haiwen Tian、Xueqin Yuan、Shuangyan Li、Chongkuan Zhou、Jianping Liu
DOI:10.1002/anie.201308642
日期:2014.1.3
Direct dehydrative α‐alkylation reactions of ketones with alcohols are now realized under simple, practical, and green conditions without using external catalysts. These catalyst‐free autocatalyzed alkylation methods can efficiently afford useful alkylated ketone or alcohol products in a one‐pot manner and on a large scale by CC bond formation of the in situ generated intermediates with subsequent
Cyclopentadienone iron dicarbonyl complexes were applied in the alkylation of ketones with various aliphatic and aromatic ketones and alcohols via the borrowing hydrogen strategy in mild reaction conditions. DFT calculations and experimental works highlight the role of the transition metal Lewis pairs and the base. These iron complexes demonstrated a broad applicability in mild conditions and extended
copper-catalyzed C–N bond cleavage of aromatic methylamines was developed to construct pyridine derivatives. With neat conditions and facile operation, the fragment-assembling strategy affords a broad range of 2,4,6-trisubstituted pyridines in up to 95% yield from simple and readily available starting materials. Interestingly, when pyridin-2-yl methylamine was employed as the substrate, α-alkylation reaction
Visible‐Light‐Induced C4‐Selective Functionalization of Pyridinium Salts with Cyclopropanols
作者:Mari Vellakkaran、Taehwan Kim、Sungwoo Hong
DOI:10.1002/anie.202113658
日期:2022.1.3
Visible-light-induced β-carbonyl alkylation of pyridines was developed by employing various cyclopropanols and N-amidopyridinium salts under mild conditions. This method provides an effective tool for the synthesis of valuable β-pyridyl-functionalized carbonyl frameworks with excellent C4 selectivity and the late-stage functionalization of complex and medicinally relevant molecules.
By employing an easily available [Ru(p-cymene)Cl-2](2)/Xantphos/t-BuOK catalyst system, the alpha-alkylation of ketones was demonstrated by using pyridyl methanol as the alkylating reagents. The synthetic protocol allows synthesizing a wide range of alpha-pyridyl methylated ketones in reasonable to excellent isolated yields with high atom-efficiency. The transformation is operationally simple, the substrate scope is wide, and the starting materials are readily-available. There is no need for addition of alkenes as the hydrogen receptors or the use of stoichiometric amount of base. (C) 2013 Elsevier Ltd. All rights reserved.