A few new d‐mannitol‐based monoaza‐15‐crown‐5 type chiral lariat ethers and 18‐crown‐6 type macrocycles were synthesized. These crown compounds were used as phasetransfercatalysts in asymmetric Michael addititons and in a Darzens condensation under mild conditions to afford the corresponding products in a few cases in good to excellent enantioselectivities. In the Michael addition of diethyl acetoxymalonate
Rh<sub>2</sub>(esp)<sub>2</sub>: An Efficient Catalyst for O-H Insertion Reactions of Carboxylic Acids into Acceptor/Acceptor Diazo Compounds
作者:Arianne C. Hunter、Kiran Chinthapally、Indrajeet Sharma
DOI:10.1002/ejoc.201600064
日期:2016.5
Rh2(esp)2 has been identified as a highly efficient catalyst for O–H insertion of carboxylic acids into acceptor/acceptor diazocompounds. The insertion reaction proceeds in CH2Cl2 within minutes at room temperature in excellent yields and accommodates carboxylic acids having varying functionalities including amino acids, free alcoholic and phenolic O–H, indole N–H, alkenes, alkynes, and substituted
The degradation of carboxylic acids into aldehydes
作者:Gábor Doleschall、Gábor Tóth
DOI:10.1016/s0040-4020(01)83135-5
日期:1980.1
developed for degradation of carboxylicacid into aldehydes containing one C atom less whose key step consists in α-acetoxylation of 5-alkyl-3-methylthio-1,4-diphenyl-1,2,4-triazolium iodides by (diacetoxyiodo)benzene. The mechanism of the regioselective α-acetoxylation was studied and the diacetoxyiodate(1)anion was shown to be the actual oxidising agent. Further oxidation reactions of tetraethylammonium
Abstract β-Dicarbonyl compounds, phenylsulfonylacetate, cyanoacetate and malonitrile sodium enolates add to β-nitroenones at the α-carbon atom of the unsaturated carbonyl system and provide access to highly functionalised intermediates.
used as phase transfer catalysts in asymmetric Michaeladdition reactions under mild conditions to afford the adducts in a few cases in good to excellent enantioselectivities. The addition of 2‐nitropropane to trans‐chalcone, and the reaction of diethyl acetamidomalonate with β‐nitrostyrene resulted in the chiral Michael adducts in good enantioselectivities (90% and 95%, respectively). The substituents