A Chemoselective Route to β-Enamino Esters and Thioesters
摘要:
Conditions were developed for syntheses of beta-enamino esters, thioesters, and amides. These reactions involve hydroxybenzotriazole derivatives in buffered media. Illustrative syntheses of some heterocyclic systems are given, including some related to protein protein interface mimics.
Efficient Synthetic Method for β-Enamino Esters Catalyzed by Yb(OTf)3 under Solvent-Free Conditions
作者:Ravi Varala、Sreelatha Nuvula、Srinivas R. Adapa
DOI:10.1071/ch06239
日期:——
esters have been synthesized in moderate to excellent yields by reacting 1,3-dicarbonyl compounds with amines in the presence of catalytic amounts of Yb(OTf)3 (2 mol%). The reaction proceeds smoothly at ambient temperature undersolvent-freeconditions. The catalyst can be recovered and reused.
The stereoselective syntheses of spirobicyclic and tetracyclic pyrazolidinones are reported based on a (3+2) annu- lation between hydrazones and α-oxoketenes. Some of these conformationally constrained molecules were resolved as enantiopure materials by HPLC techniques and evaluated as amino- catalysts for iminium activation in a model Diels–Alder cyclo- addition.
I2/TBHP promoted oxidative C–N bond formation at room temperature: Divergent access of 2-substituted benzimidazoles involving ring distortion
作者:Moumita Saha、Asish R. Das
DOI:10.1016/j.tetlet.2018.05.028
日期:2018.6
A new ‘one pot’ tandemsynthesis of 2-substituted benzimidazoles has been developed from 2-aminobenzyl alcohol/2-aminobenzamide and different coupling partners (nitriles, aldehydes and 1,3-diketones) via iodine and TBHP promoted oxidative ringcontraction. The present strategy involves sequential C–N bond formation, cyclization, subsequent ringcontraction and dehydrogenation to afford various medicinally
Visible-light-driven radical 1,3-addition of selenosulfonates to vinyldiazo compounds
作者:Weiyu Li、Lei Zhou
DOI:10.1039/d1gc02036f
日期:——
radical 1,3-selenosulfonylation of vinyldiazo compounds with selenosulfonates, providing various γ-seleno allylic sulfones in good yields. This photochemical reaction was carried out at room temperature in an open flask using ethyl acetate as the solvent without any photocatalysts or additives. The control experiments corroborated that the 1,3-addition proceeded via a radical-chain propagation process. The
Formation of trisubstituted buta-1,3-dienes and α,β-unsaturated ketones <i>via</i> the reaction of functionalized vinyl phosphates and vinyl phosphordiamidates with organometallic reagents
ester functional group with organometallic reagents. We found that the functionalized vinyl phosphates were smoothly converted into tri- and tetrasubstituted buta-1,3-dienes via the reaction with aryllithium reagents. Moreover, the vinyl phosphordiamidates were converted into α,β-unsaturated ketones using Grignard reagents. Based on the performed experiments, we proposed a reaction mechanism, which was