89506-40-1Relevant articles and documents
Mild Homologation of Esters through Continuous Flow Chloroacetate Claisen Reactions
Ganiek, Maximilian A.,Ivanova, Maria V.,Martin, Benjamin,Knochel, Paul
supporting information, p. 17249 - 17253 (2018/12/05)
The selective chloromethylenation of functionalized esters using chloroacetic acid (CA) and LiHMDS (HMDS=hexamethyldisilazide) in a continuous-flow setup is reported. This Claisen homologation is for the first time extended to bis-chloromethylenation using dichloroacetic acid (DCA), thus giving access to under-explored α,α′-bis-chloroketones. The use of flow conditions enables efficient generation and reaction of the unstable chloroacetate dianion intermediates, leading to unprecedented mild and scalable reaction conditions at an economical reagent stoichiometry (?10 °C, 1 min, 1.0–2.4 equiv dianion). The clean reaction profiles allow subsequent use of the unpurified crude products, which is demonstrated in the synthesis of various heterocycles of broad interest. Furthermore, we report a novel, catalyst-free substitution of the obtained monochloro ketone products with (hetero)aryl zinc enolates to give valuable 1,4-diketones.
Addition of Aldehydes to Activated Double Bonds, XXXIV. Addition of Aldehydes to Cyclic α-Methylene Ketones
Stetter, Hermann,Haese, Wilfried
, p. 682 - 693 (2007/10/02)
The thiazolium salt-catalyzed addition of aldehydes to the cyclic α-methylene ketones 3, 4, 7, 8, 48, and 49 leads to γ-diketones 9 - 22, 50 - 53; some of them were converted into unsaturated ketones 23 - 28, pyrroles 29 - 34, 37 - 43, and furans 35, 36,
