Catalyticasymmetric protonation of chiral calcium enolates was performed. Chiral calcium enolates, prepared in situ from imides and malonates via 1,4-addition in the presence of catalytic amounts of Ca(OEt)(2), Ph-PyBox, and achiral phenol, were smoothly protonated to afford adducts bearing tertiary asymmetric carbons in high yields with high enantioselectivities. The adducts were readily converted
efficient and convenient copper-mediated method has been developed to achieve direct cascadeC–H/N–H annulation to synthesize 2-quinolinones from electron-deficient acrylamides and arynes. This method highlights an emerging but simple strategy to transform inert C–H bonds into versatile functional groups in organic synthesis to provide a new method of synthesizing 2-quinolinones efficiently. Mechanistic
Es wird die Synthese von Vertretern der bisher unbekannten Isoxazolidin-3,5-dione durch Umsetzung von Hydroxylamin oder N-monosubstituierten Hydroxylaminen mit substituerten Malonsäurechloriden beschrieben. Eine Anzahl der neuen Verbindungen wirken im Tierexperiment antiphlogistisch.
copper-catalyzed aerobic oxidative azo-ene cyclization has been developed. The developed CuI/DMAP/O2 system efficiently facilitates the aerobic oxidation of ene-containing hydrazides to azo compounds, which undergo azo-ene cyclizations for the synthesis of oxazolidinones. In addition, the present approach enables the synthesis of lactams, as well as a nitroso-ene cyclization. Preliminary mechanistic
challenging intramolecular hydroacyloxylation reaction. Both HFIP and an internal carboxy group have been proven to be crucial for the successful implementation of this transformation; these are proposed to assist the formation and stabilization of the key cationic intermediate via hydrogen-bondinginteractions with perrhenate anion (ReO4–).
该出版物描述了 Re 2 O 7在六氟异丙醇 (HFIP) 中的应用,用于活化惰性和电子失活的烯烃,以促进具有挑战性的分子内加氢酰氧基化反应。HFIP 和内部羧基均已被证明对于成功实施这一转变至关重要;这些被提议通过与高铼酸盐阴离子 (ReO 4 – )的氢键相互作用来帮助关键阳离子中间体的形成和稳定。