Palladium-catalyzed substitution reactions of 4-allylimidazole derivatives
作者:Pasupathy Krishnamoorthy、Rasapalli Sivappa、Hongwang Du、Carl J. Lovely
DOI:10.1016/j.tet.2006.05.090
日期:2006.11
required an efficient method for conducting substitutionreactions of allylic alcohols derived from urocanic acid. While in some cases this could be accomplished quite readily by classical nucleophilic substitution, it was complicated by allylic transposition in others. Application of Pd-catalyzed π–allyl chemistry provided a convenient solution, giving substitution without allylic transposition. Herein
New enolate-carbodiimide rearrangement in the concise synthesis of 6-amino-2,3-dihydro-4-pyridinones from homoallylamines
作者:N. Yu. Kuznetsov、R. M. Tikhov、I. A. Godovikov、V. N. Khrustalev、Yu. N. Bubnov
DOI:10.1039/c6ob00293e
日期:——
Three-step synthesis of 6-amino-2,3-dihydro-4-pyridinones from homoallylamines involving NBS (or I2, PhSeCl)-mediated cyclization of N-(3-butenyl)ureas to 6-(bromomethyl)-2-iminourethanes, dehydrohalogenation and the novel enolate-carbodiimide rearrangement as a key step has been developed. The...
amount of DBU in DCM, N-p-toluenesulphonyl carbamates 6a–c, prepared starting from the corresponding Baylis–Hillman adducts, gave (E)-2-(p-toluenesulphonylaminomethyl)propenoates 3a–c, exclusively. On the contrary, changing DABCO for DBU, 2-methylene-3-p-toluenesulfonylamino esters 4a–f were obtained in good yield starting from N-p-toluenesulphonyl carbamates 6a–f. In analogy, N-acyl carbamates 9a–f were
Ir(I)-catalyzed decarboxylative allylic amidation of chiral branched benzyl allyl imidodicarboxylates has been shown to proceed with complete retention of enantiomeric purity and configuration. The transformation is stereospecific and appears to be quite general, accommodating a wide range of R groups.