Ferric Chloride Hexahydrate-Catalyzed Highly Regio- and Stereoselective Conjugate Addition Reaction of 2,3-Allenoates with Grignard Reagents: An Efficient Synthesis of β,γ-Alkenoates
作者:Guobi Chai、Zhan Lu、Chunling Fu、Shengming Ma
DOI:10.1002/adsc.200900091
日期:2009.8
Ferricchloride hexahydrate was shown to be an efficient catalyst for the conjugate addition of 2,3-allenoates with alkyl-, aryl-, or vinyl-Grignard reagents to synthesize polysubstituted β,γ-unsaturated alkenoates with high regio- and stereoselectivity. The in situ formed magnesium dienolate may readily react with different electrophilic reagents under different reaction conditions with or without
Studies on Electrophilic Interaction of 2,3-Allenols with Electrophilic Halogen Reagents: Selective Synthesis of 2,5-Dihydrofurans, 3-Halo-3-alkenals, or 2-Halo-2-alkenyl Ketones
作者:Jing Li、Chunling Fu、Guofei Chen、Guobi Chai、Shengming Ma
DOI:10.1002/adsc.200800088
日期:2008.6.9
iodine (I2) afforded 2,5-dihydrofurans while that of readily available 1-aryl or 1-methyl substituted 2,3-allenols with bromine (Br2), N-bromosuccinimide (NBS), I2 or N-iodosuccinimide (NIS) formed the not easily available but synthetically useful 3-halo-3-alkenals and 2-halo-2-alkenyl ketones with good selectivity and yields via a sequential electrophilic interaction of X+ with the allene moiety, 1,2-aryl
Chemistry of Heterocyclic Ketene Aminals: Construction of Imidazo(pyrido)[1,2-<i>a</i>]pyridines and Imidazo(pyrido)[3,2,1-<i>ij</i>][1,8]naphthyridines via DABCO-Catalyzed Tandem Annulations
2-(2-Chloroaroyl)methyleneimidazolidines with four reactive sites show fascinating structural features and could be used as a new strategy for the synthesis of novel heterocycles. This paper presents our new findings in the reaction of 2-(2-chloroaroyl)methyleneimidazolidines with allenic esters affording functionalized imidazo(pyrido)[1,2-a]pyridines via DABCO-catalyzed tandem annulations. Of particular
具有四个反应位点的2-(2-氯代芳酰基)亚甲基咪唑烷显示出令人着迷的结构特征,可以用作合成新杂环的新策略。本文介绍了我们的新发现,在2-(2-氯芳酰基)亚甲基咪唑烷与烯丙酸酯的反应中,通过DABCO催化串联环合提供官能化的咪唑并(吡啶基)[1,2- a ]吡啶。特别重要的是掺入ø卤代组成的2-benzoylmethylene-咪唑烷芳基环,以建立一个方便的和一般的方式用于构造不寻常的咪唑并(吡啶基)[3,2,1 IJ ] [1,8萘啶。
Reaction of 2,3-Allenoates with TsNBr<sub>2</sub> in the Presence of Base: A Facile Highly Stereoselective Synthesis of (1<i>E</i>,2<i>E</i>)-3-Bromo-4-oxo-<i>N</i>‘-tosyl-2-alkenoxylimidic Acid Ethyl Esters
作者:Ruwei Shen、Xian Huang
DOI:10.1021/jo070239z
日期:2007.5.1
A novel reaction pathway of 2,3-allenoates with an electrophile (TsNBr2) in the presence of K2CO3 to produce (1E,2E)-3-bromo-4-oxo-N‘-tosyl-2-alkenoxylimidic acidethylesters is reported. The reaction proceeds in a highly stereoselective fashion. A plausible mechanism to rationalize this reaction is also proposed.
在K 2 CO 3存在下2,3-脲基酸酯与亲电试剂(TsNBr 2)的新反应途径产生(1 E,2 E)-3-bromo-4- oxo- N'-甲苯磺酰基-2-报道了烯氧基氧酰亚胺酸乙酯。反应以高度立体选择性的方式进行。还提出了合理化该反应的合理机制。