Mild Approach to the Deprotection of Troc from Protected Amines Using Mischmetal and TMSCl
摘要:
The 2,2,2-trichloroethoxycarbonyl (Troc) protecting group was efficiently removed from Troc-protected aliphatic and aromatic amines and also some Troc, Tos- and Troc, Ac-protected amines using activated mischmetal (MM). All reactions were performed by refluxing in dry tetrahydrofuran under an argon atmosphere and gave moderate to excellent yields. Several new compounds were synthesized, and new data about reactivity of Troc group were obtained.
在良性条件下通过直接自由基-自由基交叉偶联来构建C(sp 3)-N键是一种理想但具有挑战性的方法。在此,通过镍/光氧化还原双重催化,以简明,温和且无氧化剂的方式将烷基和and基自由基交叉偶联以建立脂族C–N键。在该协议中,成功地采用了单电子转移策略,分别从磺酰基叠氮化物/叠氮基甲酸酯和烷基三氟硼酸酯生成N-和C-中心的自由基。然而,光催化剂诱导的三重态-三重态能量转移机制可能不适用于该反应。激发的光催化剂(Ru II / * Ru II / Ru III / Ru II的氧化猝灭途径))结合可能的Ni I / Ni II / Ni III / Ni I催化循环,基于协同实验和计算研究,提出了镍/光氧化还原双催化C(sp 3)–N键形成的方法。
Amino groups are selectively protected in good yields by reaction with O-alkyl S-(pyridin-2-yl)carbonothiolates in an appropriate solvent at room temperature in air. Even glucosamine, which contains multiple hydroxyl groups, is selectively N-protected in methanol.
通过与 O-烷基 S-(吡啶-2-基)碳硫醇盐在适当的溶剂中在室温下在空气中反应,氨基以良好的产率被选择性地保护。甚至含有多个羟基的葡糖胺也在甲醇中被选择性地 N 保护。
De Novo Synthesis of Troc-Protected Amines: Intermolecular Rhodium-Catalyzed C−H Amination with <i>N</i>-Tosyloxycarbamates
作者:Hélène Lebel、Kim Huard
DOI:10.1021/ol062953t
日期:2007.2.1
intermolecular C-Hinsertion of the nitrene derived from 2,2,2-trichloroethyl-N-tosyloxycarbamate proceeded in good to excellent yields to produce a variety of Troc-protected amines. With cyclic aliphatic alkanes, it is possible to use only 2 equiv of substrate, whereas the reaction with aromatic alkanes is run neat. Not only does the nitrene insertion proceed in benzylic, secondary, and tertiary C-H bonds
<i>N</i>‐Tosyloxycarbamates as Reagents in Rhodium‐Catalyzed CH Amination Reactions
作者:Kim Huard、Hélène Lebel
DOI:10.1002/chem.200702027
日期:2008.7.7
nitrenes for use in C-Hinsertion reactions were obtained from N-tosyloxycarbamates in the presence of an inorganic base and a rhodium(II) dimer complex catalyst. The C-H amination reaction proceeds smoothly, and the potassium tosylate that forms as a byproduct is easily removed by filtration or an aqueous workup. This new methodology allows the amination of ethereal, benzylic, tertiary, secondary
A Facile and Efficient Method for the Formation of Unsymmetrical Ureas Using DABAL-Me3
作者:Byung-Hoon Jeong、Hee-Kwon Kim、David H. Thompson
DOI:10.1071/ch15675
日期:——
A practical synthetic method for the formation of unsymmetrical-substituted ureas is described. The synthesis of the unsymmetrical ureas was readily performed from 2,2,2-trichloroethyl carbamate compounds by treatment of amines with bis(trimethylaluminum)-1,4-diazabicyclo[2.2.2]octane (DABAL-Me3). Using this reaction protocol, various trisubstituted and tetrasubstituted ureas were synthesized in high
1,1′-Bis[6-(trifluoromethyl])benzotriazolyl] carbonate (BTBC) was prepared from 1-hydroxy-6-trifluoromethylbenzotriazole and trichloromethyl chloroformate (trichloromethyl carbonochloridate). The reaclion of BTBC and alcohols afforded the corresponding active carbonates which were converted into the corresponding carbamates and carbonates.