Rhodium Catalyzed Asymmetric Hydrogenation of 2-Pyridine Ketones
摘要:
Catalyzed by [Rh(COD)Binapine]BF4, the asymmetric hydrogenation of 2-pyridine ketones has been achieved with excellent enantioselectivities (enantiomeric excesses up to 99%) under mild conditions. This method is suitable for various kinds of 2-pyridine ketones and their derivatives. A number of enantiomerically pure chiral 2-pyridine-aryl/alkyl alcohols were prepared through hydrogenation, which can be used directly in organic synthesis.
Aggregative activation in heterocyclic chemistry. Part 5.† Lithiation of pyridine and quinoline with the complex base BuLi·Me2N(CH2)2OLi (BuLi·LiDMAE)
作者:Philippe Gros、Yves Fort、Paul Caubère
DOI:10.1039/a705027e
日期:——
It is shown that the complex base BuLi·LiDMAE reacts with pyridine to give metallated species which, after trapping by electrophiles, lead to 2-substituted pyridines in good to excellent yields. The same reactions have been less successfully performed with quinoline.
Barbier type reaction with lithium metal has been tested under sonication on pyridines, a cinnoline and on various diazines. This very convenient method allows a very fast and smooth functionalization of these heterocycles.
Bromine–magnesium exchange using iPrMgCl in THF at roomtemperature on 2-, 3- and 4-bromopyridines allowed the synthesis of various functionalized pyridines. The methodology was successfully used for the synthesis of 4-azaxanthone. Moreover, single exchange reactions observed on 2,6-, 3,5-, 2,3- and 2,5-dibromopyridines, with complete regioselectivity in the case of 2,3- and 2,5-dibromopyridines, afforded
[EN] PROCESSES FOR PRODUCING alpha -PYRIDYL CARBINOLS
申请人:——
公开号:WO1992019596A2
公开(公告)日:1992-11-12
[EN] Disclosed are preferred processes for producing alpha -2-pyridyl alpha -aryl carbinol or alpha -4-pyridyl alpha -aryl carbinol compounds. [FR] Procédés de production de composés alpha-2-pyridyle alpha-aryl-carbinol ou alpha-4-pyridyle alpha-aryl-carbinol.