A detailed investigation of the aza-Prins reaction
作者:Adrian P. Dobbs、Sebastien J. J. Guesné、Robert J. Parker、John Skidmore、Richard A. Stephenson、Mike B. Hursthouse
DOI:10.1039/b915797b
日期:——
The development of a Lewis acid-promoted aza-Prins reaction to form piperidines and pyrrolidines is described. Indium trichloride has been found to be a highly successful and mild Lewis acid for promoting this reaction. A thorough mechanistic investigation is described, including the factors that influence the formation of the 5- or 6-membered ring product(s).
Transition Metal Free Cycloamination of Prenyl Carbamates and Ureas Promoted by Aryldiazonium Salts
作者:Roman Abrams、Quentin Lefebvre、Jonathan Clayden
DOI:10.1002/anie.201809323
日期:2018.10.8
O‐prenyl carbamates cyclize in a photocatalytic reaction with visiblelight and an organic dye. With electron‐deficient diazonium salts, electronic matching with an electron‐rich N‐aryl substituent results in a reaction proceeding in the ground state, without either light or photocatalyst. Cyclic voltammetry suggests that this radical reaction is initiated by hydrogen‐atomabstractionmediated by an aryl radical
The intramolecularcyclopropanation of various trans-allylic diazoacetates and alkenyl diazoketones has been achieved with excellent enantioselectivities of up to 98% ee and in quantitative yields by using a water-solubleruthenium(II)/hydroxymethyl(phenyl)oxazoline catalyst in a water/ether biphasic medium. The catalyst could be reused at least five times.
Synthesis of N−H Bearing Imidazolidinones and Dihydroimidazolones Using Aza‐Heck Cyclizations
作者:Feiyang Xu、Scott A. Shuler、Donald A. Watson
DOI:10.1002/anie.201806295
日期:2018.9.10
The synthesis of unsaturated, unprotected imidazolidinones via an aza‐Heck reaction is described. This palladium‐catalyzed process allows for the cyclization of N‐phenoxy ureas onto pendant alkenes. The reaction has broad functional group tolerance, can be applied to complex ring topologies, and can be used to directly prepare mono‐ and bis‐unprotected imidazolidinones. By addition of Bu4NI, dihydroimidazolones
One-Pot Conversion of <i>N</i>-Allyl-α-cyano Esters to α-Allyl-α-cyano Lactams through a Hydrolysis/Ketene Formation/Cyclization/Claisen Rearrangement Sequence
作者:Mei-Hua Shen、Mei Han、Hua-Dong Xu
DOI:10.1021/acs.orglett.5b02843
日期:2016.3.4
An intramolecular ketene aza-Claisen rearrangement is developed for the first time to enable the stereoselective synthesis of α-ally-α-cyano-lactams from N-allyl amino esters. This reaction also exhibits outstanding chemoselectivity when an unsymmetrical bis-N-allyl group is present in the starting molecule. The usefulness of this method is demonstrated by a short synthesis of optically active bicyclolactam