Cycloaddition Reaction of Mesoionic 4-Trifluoroacetyl-1,3-oxazolium-5-olates with Enamines Affording 2-Trifluoroacetylpyrroles
作者:Ryosuke Saijo、Masami Kawase
DOI:10.1002/ejoc.201801728
日期:2019.2.21
Mesoionic 4‐trifluoroacetyl‐1,3‐oxazolium‐5‐olates (münchnones) reacted with enamines to yield densely functionalized 2‐trifluoroacetylpyrroles. The trifluoroacetic acid addition in the reaction was the key for the good yields of the 1,3‐dipolar cycloaddition product. DFT calculations were performed for the 1,3‐dipolar cycloadditions of münchnones and enamines.
Phosphorated 1,2-Oxazabuta-1,3-dienes as Synthetic Tools for the Preparation of <i>α</i>-Amino Phosphorus Derivatives and Functionalized Nitrogen-Containing Heterocycles
作者:Jesús M. de los Santos、Roberto Ignacio、Domitila Aparicio、Francisco Palacios
DOI:10.1080/10426507.2010.522632
日期:2011.3.31
Abstract An efficient method for the synthesis of phosphorated 1,2-oxazabuta-1,3-dienes derived from phosphine oxides and phosphonates has been developed by means of base-mediated dehydrohalogenation of readily available α-halooximes. New functionalized α-amino phosphorus derivatives are easily available, in a regioselective way, through conjugate addition of amino nucleophilic reagents such as ammonia
Acyclic and Heterocyclic Azadiene Diels–Alder Reactions Promoted by Perfluoroalcohol Solvent Hydrogen Bonding: Comprehensive Examination of Scope
作者:Zixi Zhu、Dale L. Boger
DOI:10.1021/acs.joc.2c02000
日期:2022.11.4
cycloaddition are defined; new viable diene/dienophile reaction partners in the cycloaddition reactions are disclosed; and key comparison rate constants are reported. The perfluoroalcohol effectiveness at accelerating an inverseelectrondemandDiels–Alder cycloaddition is directly correlated with its H-bond potential (pKa). Not only are the reactions of electron-rich dienophiles accelerated but those
本文描述了全氟醇氢键在加速无环氮杂二烯逆电子需环加成反应中的首次应用,并通过对全系列氮杂二烯的研究推广了其在促进杂环氮杂二烯环加成反应中的应用。全面探讨了亲双烯体的范围;确定了亲二烯体和氮杂二烯的相对反应性趋势和溶剂相容性;定义了导致速率提高、产率提高的氢键溶剂效应及其对区域选择性和环加成模式的影响;公开了环加成反应中新的可行的二烯/亲双烯体反应伙伴;并报告了关键的比较速率常数。全氟醇加速逆电子需求狄尔斯-阿尔德环加成反应的有效性与其氢键势 (p Ka )直接相关。不仅富电子亲双烯体的反应得到加速,而且应变甚至未活化的烯烃和炔烃的反应也得到改善,包括代表性的生物正交点击反应。
Diels-Alder Reaction of 1,2,3-Triazine with Aldehyde Enamine
作者:Junko Koyama、Tamaki Ogura、Kiyoshi Tagahara
DOI:10.3987/com-94-6727
日期:——
The Diels-Alder reaction of 4-methyl-1,2,3-triazine with several aldehyde enamines was carried out to afford 2,5-disubstituted pyridines. As an application of this method, we accomplished the synthesis of alkaloid, fusaric acid.