Iridium-Catalyzed Highly Enantioselective Transfer Hydrogenation of Aryl <i>N</i>-Heteroaryl Ketones with <i>N</i>-Oxide as a Removable <i>ortho</i>-Substituent
作者:Qixing Liu、Chunqin Wang、Haifeng Zhou、Baigui Wang、Jinliang Lv、Lu Cao、Yigang Fu
DOI:10.1021/acs.orglett.7b03878
日期:2018.2.16
A highlyenantioselectivetransferhydrogenation of non-ortho-substituted aryl N-heteroaryl ketones, using readily available chiral diamine-derived iridium complex (S,S)-1f as a catalyst and sodium formate as a hydrogen source in a mixture of H2O/i-PrOH (v/v = 1:1) under ambient conditions, is described. The chiral aryl N-heteroaryl methanols were obtained with up to 98.2% ee by introducing an N-oxide
使用容易获得的手性二胺衍生的铱络合物(S,S)-1f作为催化剂,甲酸钠作为氢源的H 2 O混合物,对非邻位取代的芳基N-杂芳基酮进行高度对映选择性转移氢化/我的i-PrOH(v / v = 1:1)在环境条件下,进行说明。通过引入N-氧化物作为可除去的邻位取代基,获得具有高达98.2%ee的手性芳基N-杂芳基甲醇。相反,在不存在氮的情况下,观察到的ee不超过15.1%-氧化物部分。此外,该协议的实用性还通过克规模的苯磺酸他莫司汀的克级不对称合成以51%的总收率和99.9%的ee进行了证明。
Intramolecular radical additions to pyridines
作者:David C. Harrowven、Benjamin J. Sutton、Steven Coulton
DOI:10.1039/b309331j
日期:——
carbon tether is employed, leading to products derived from hydrogen atom abstraction, ipso-cyclisation and ortho-cyclisation pathways. All attempts to effect 5-exolendo-trig cyclisations failed. Tributyltin hydride, tris(trimethylsilyl)silane, tris(trimethylsilyl)germane and, in part, samarium(II) iodide can each be employed as mediators of the reaction.
Lewis acid complexed heteroatom carbanions; synthesis of some α-pyridyl alcohols
作者:Satinder V. Kessar、Paramjit Singh、Kamal Nain Singh、Mahesh Dutt
DOI:10.1039/c39910000570
日期:——
Metallation of BF3âpyridine complex with lithium tetramethylpiperidide (LTMP) in ether at â78 °C, followed by reaction with carbonyl compounds, affords α-pyridyl alcohols in good yields.