Tunable Synthesis of 3-Acyl-2-naphthols and 3-Substituted Isocoumarins via Jones Reagent Promoted Cascade Reactions of 2-(4-Hydroxy-but-1-ynyl)benzaldehydes
摘要:
Novel and efficient synthesis of 3-acyl-2- 1) naphthols and 3-substituted isocoumarins via the tunable cascade reactions of 2-(4-hydroxy-but-1-ynyl)benzaldehydes have been developed. Treatment of 2-(4-hydroxy-but-1-ynyl)benzaldehydes with 0.7 equiv of Jones reagent in CH3CN and subsequent purification through column chromatography on silica gel pre-eluted with Et3N afforded 3-acyl-2-naphthols with high efficiency. When the same substrates were treated with 3 equiv of Jones reagents in acetone, on the other hand, 3-substituted isocoumarins could be obtained in good yields.
Regioselective propargylation of aldehydes using potassium allenyltrifluoroborate promoted by tonsil
摘要:
The propargylation of aldehydes using potassium allenyltrifluoroborate promoted by tonsil, an inexpensive and readily available clay, in a chemo- and regioselective way is described. The method is simple and avoids the use of air and moisture sensitive organometallics and products were obtained in good to moderate yields. (C) 2016 Elsevier Ltd. All rights reserved.
Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation
作者:Jucleiton J R Freitas、Queila P S B Freitas、Silvia R C P Andrade、Juliano C R Freitas、Roberta A Oliveira、Paulo H Menezes
DOI:10.3762/bjoc.16.19
日期:——
The propargylation of aldehydes promoted by microwaveirradiation using allenylboron compounds in a chemo- and regioselective way is described. The corresponding products were obtained in short reaction time, high yield and purity without the need of any solvent when allenylboronic acid pinacol ester was used, or using a minimal amount of acetone when potassium allenyltrifluoroborate was used.
quite scarce. We describe an extremely mild and selective method for either the propargylation or allenylation of carbonyl compounds catalyzed by the abundant, safe, and inexpensive metal titanium. These reactions can selectively provide homopropargylic alcohols from aldehydes and ketones or α‐hydroxy‐allenes from aldehydes. The mechanisms involved were also investigated.
Scalable Regioselective and Stereoselective Synthesis of Functionalized (<i>E</i>)-4-Iodobut-3-en-1-ols: Gram-Scale Total Synthesis of Fungal Decanolides and Derivatives
作者:Alexander M. Sherwood、Samuel E. Williamson、Stephanie N. Johnson、Anil Yilmaz、Victor W. Day、Thomas E. Prisinzano
DOI:10.1021/acs.joc.7b02324
日期:2018.1.19
A reliable protocol to synthesize both racemic and chiral (E)-4-iodobut-3-en-1-ols from aldehydes or epoxides, respectively, containing various aromatic and aliphatic substitutions has been established. The utility of these compounds was then demonstrated by providing access to known fungal decanolides as well as novel aromatic macrocycles. The protocol provided a gram-scale route to (−)-aspinolide
Formal metal-free γ-arylation of 1,3-dicarbonyl compounds <i>via</i> an isomerisation/1,4-addition/[3,3]-sigmatropic rearrangement sequence
作者:Shi-Chao Lu、Fu-Qiang Wen、Xi-Dong Guan
DOI:10.1039/d1gc02856a
日期:——
metal-free redox arylation of alkynes with sulfoxides has been developed to provide unconventional access to diverse γ-arylated 1,3-dicarbonyl compounds in an atom-economical manner. Mechanistic studies suggest that a conjugated allenone intermediate was generated in situ, which solves the problem of reactivity and regioselectivity of unsymmetrical dialkyl-substituted internalalkynes and enables the functionalisation
Tandem Reactions of 1,2-Allenic Ketones Leading to Substituted Benzenes and α,β-Unsaturated Nitriles
作者:Xinying Zhang、Xuefei Jia、Liangliang Fang、Nan Liu、Jianji Wang、Xuesen Fan
DOI:10.1021/ol201789z
日期:2011.10.7
One-pot double Michaeladdition/intramolecular aldol reaction/decarboxylation of 1,2-allenic ketones with cyanoacetate offers an efficient and convenient approach to highly functionalized benzenes. With 2-substituted cyanoacetates, the reaction proceeds via a different tandem process to afford α,β-unsaturatednitriles effectively.