Asymmetric Synthesis of 3,4,6-Trisubstituted 2,5-Diketopiperazines by Using Dynamic Kinetic Resolution of α-Bromo Tertiary Acetamides
作者:Jinho Baek、Seock Yong Kang、Chan Im、Yong Sun Park
DOI:10.1002/ejoc.201301936
日期:2014.5
A new and efficient method for the asymmetric synthesis of 3,4,6-trisubstituted 2,5-diketopiperazines has been developed. The dynamickineticresolution of L-amino-acid-derived α-bromo tertiary amides in the nucleophilicsubstitution reaction with p-anisidine and a subsequent deprotection-cyclization process provides rapid access to diverse cis-2,5-diketopiperazines 5a–5o and proline-containing trans-2
Rhodium-catalyzed coupling of α-lactams with indole derivatives
作者:Hannah K. Box、K.G. Upul Kumarasinghe、Radhika R. Nareddy、Gopalakrishna Akurathi、Amarraj Chakraborty、Babatunde Raji、Gerald B. Rowland
DOI:10.1016/j.tet.2014.10.049
日期:2014.12
for the formation of a C–N bond between the C–3 carbon of α-lactams and the nitrogen atom of indoles. A general procedure for the coupling of indoles and α-lactams in only 25 min with high yield is reported. The scope of the reaction was extended by the development of a method for the in situ generation of less stable phenyl-substituted α-lactams. The developed method provides an atom-economical method
<i>tert-</i>Butyl Hydroperoxide and Tetrabutylammonium Iodide-Promoted Free Radical Cyclization of α-Imino-<i>N</i>-arylamides and α-Azido-<i>N</i>-arylamides
作者:Dianjun Li、Tonghao Yang、Hailin Su、Wei Yu
DOI:10.1002/adsc.201500305
日期:2015.8.10
The oxidizing system of tert‐butyl hydroperoxide (TBHP) and tetrabutylammonium iodide (TBAI) is capable of generating α‐(arylaminocarbonyl)iminyl radicals from ethyl 2‐(N‐arylcarbamoyl)‐2‐iminoacetates. These iminyl radicals preferably undergo intramolecular ipso attack on the benzene ring to give azaspirocyclohexadienyl radicals, which are readily captured by molecular oxygen under an oxygen atmosphere
4-Ethyl-3-(phenyl)-1-(3-trifluoromethylphenyl)-2-pyrrolidinones and corresponding compounds bearing a p-substituent on the 1-position phenyl group and/or a substituent on the 3-position phenyl group exhibit selective herbicidal activities against various weeds which cause problems in rice or upland fields, even at extremely low application rates. They can be prepared by reductive dehalogenation of a corresponding .alpha.-haloethyl substituted pyrrolidinone or reductive cyclization of a corresponding N-2-butenyl-N-(substituted phenyl)-haloacetyl-3-trifluoromethylaniline.