Comparison of Large-Scale Routes to Manufacture Chiral exo-2-Norbornyl Thiourea
摘要:
Two routes aimed at the manufacture of chiral exo-2-norbornyl thiourea (1) on large scale are described. The first approach involves live chemical steps and hinges on a classical resolution via diastereomeric salt formation. The synthesis utilizes amine 2 as the resolution handle. The second approach includes two chemical steps and a chiral chromatography of (+/-)-1. Despite the larger initial investment necessary to acquire the chiral stationary phase used in the chromatographic approach, the shorter reaction sequence and efficiency of the chromatographic separation make the second route a more attractive option tor long-term applications.
The synthesis of various new 1-aminated-2,5-cyclohexadienes is described. These reagents can be used in radical transfer hydroaminations of unactivated and electron-rich double bonds. With thiols as polarity reversal catalysts good yields are obtained. The radical hydroamination occurs with good to excellent anti-Markovnikov selectivity. Many functional groups such as alcohols, silyl ethers, phosphonates
Amidation of norbornene with organic nitriles in the presence of water catalyzed by iron compounds
作者:Ravil I. Khusnutdinov、Tatyana M. Oshnyakova
DOI:10.1016/j.tetlet.2015.09.131
日期:2015.11
The amidation of norbornene with various nitriles was performed in the presence of water under the action of FeCl3·6H2O to give N-(exo-2-norbornyl)acylamides in 76–95% yield.
Elemental fluorine. Part 14.1 Electrophilic fluorination and nitrogen functionalisation of hydrocarbons
作者:Richard D. Chambers、Alan M. Kenwright、Mandy Parsons、Graham Sandford、John S. Moilliet
DOI:10.1039/b204776b
日期:2002.10.1
achieved by reaction with either elemental fluorine or Selectfluor™, an electrophilic fluorinatingreagent of the N–Fclass. An electrophilic mechanism is envisaged. On prolonged reaction, the strongly acidic reaction medium that is formed upon substitution of hydrogen by fluorine when Selectfluor™ is used as the fluorinatingreagent, promotes loss of fluoride from the initial fluorinated product. Trapping
Alder; Stein, Justus Liebigs Annalen der Chemie, 1934, vol. 514, p. 197,200, 208
作者:Alder、Stein
DOI:——
日期:——
Reactions of Thianthrene Cation Radical with Acyclic and Cyclic Alcohols
作者:Henry J. Shine、Wang Yueh
DOI:10.1021/jo00092a011
日期:1994.7
Thianthrene cation radical perchlorate (Th*(ClO4-)-Cl-+) reacted readily with cycloalkanols (C-5, C-7, C-8, and C-12), alkan-2-ols (C-3, C-5, C-6, and C-8), 3-hexanol, neopentyl alcohol, a number of benzyl alcohols, dl- and (S)-1-phenylethanol, cyclopentyl- and cyclohexylmethanols, the exo- and endo-borneols, and norborneols. Reactions were carried out with an excess of the alcohol in acetonitrile solution containing 2,6-di-tert-butyl-4-methylpyridine. Products were alkenes, ethers, and N-substituted acetamides, depending on the structure of the alcohol. Thianthrene(Th) and its 5-oxide (ThO) were formed in equal amounts. The sum of amounts of products from the alcohol was equal to the amount of ThO. All reactions are interpretable on the basis of the ultimate formation and further reactions of a 5-alkoxythianthreniumyl ion (ROTh(+)). The predominant formation of nortricyclene from the norborneols is striking and is discussed. Swern-Moffatt-type oxidations of the alcohols were not observed.