Asymmetric Allylic C–H Oxidation for the Synthesis of Chromans
摘要:
An enantioselective intramolecular allylic C-H oxidation to generate optically active chromans has been accomplished under the cooperative catalysis of a palladium complex of chiral phosphoramidite ligand and 2-fluorobenzoic acid. Mechanistic studies suggest that this reaction commences with a Pd-catalyzed allylic C-H activation event and then undergoes asymmetric allylic alkoxylation. The synthetic significance of the method has been embodied by concisely building up a key chiral intermediate to access (+)-diversonol.
Access to chiral γ-butenolides <i>via</i> palladium-catalyzed asymmetric allylic C–H alkylation of 1,4-dienes
作者:Zhen-Yao Dai、Pu-Sheng Wang、Liu-Zhu Gong
DOI:10.1039/d1cc02295d
日期:——
Asymmetric allylic C–H alkylation of 1,4-pentadienes with α-angelica lactones has been developed by tri-axial phosphoramidite-palladium catalysis. This reaction can tolerate a range of functional groups under mild conditions, furnishing versatile chiral γ,γ-disubstituted butenolides in high yields with good to high levels of stereoselectivity.
已通过三轴亚磷酰胺-钯催化开发了 1,4-戊二烯与 α-当归内酯的不对称烯丙基 C - H 烷基化反应。该反应可以在温和条件下耐受一系列官能团,以高产率提供多功能手性 γ,γ-二取代丁烯内酯,具有良好到高水平的立体选择性。
Cholesteryl Ester Transfer Protein Inhibitors
申请人:Ali Amjad
公开号:US20100167986A1
公开(公告)日:2010-07-01
Compounds of Formula (I), including pharmaceutically acceptable salts of the compounds, are CETP inhibitors, and are useful for raising HDL-cholesterol, reducing LDL-cholesterol, and for treating or preventing atherosclerosis. In the compounds of Formula (I), A
1
and A
2
are each an aromatic ring, a 5-6-membered heterocyclic ring, an aromatic ring fused to a heterocyclic ring, a phenyl ring fused to a heterocyclic ring, or a cycloalkyl ring, and Z is an aromatic or heterocyclic ring.
Here we designed and synthesized a NN–CoII bidentate complex and efficiently used it for general and expedient amination of alcohols under benign, solventlessconditions. Both primary (including unactivated aliphatic) alcohols and sterically hindered secondary alcohols exhibited very good reactivity and provided diverse amines with good substrate scope (88 examples; up to 95% yields) and excellent
crystal X-ray diffraction. These catalysts were found to dehydrogenate alcoholsefficiently at temperatures as low as 50 °C to allow Schiff-base condensation and subsequent imine hydrogenation to afford secondaryamines. Notably, this ruthenium-based procedure enables the N-alkylation of aromatic and heteroaromatic primaryamines with a wide range of primaryalcohols in excellent yields of up to 98%