Electronic effects in the acid-promoted deprotection of N-2,4-dimethoxybenzyl maleimides

Novel α,α-Difluorohomophthalimides via Copper-Catalyzed Tandom Cross-Coupling−Cyclization of 2-Halobenzamides with α,α-Difluoro Reformatskii Reagent

“…Unfortunately, compound 8 remained unchanged after standard DMB removal procedures, even upon treatment with neat CF 3 CO 2 H at 60 °C for 48 h (Scheme ). The unusual stability of the fluorinated imide 8 to CF 3 CO 2 H may be explained by the high electron deficiency at the imide nitrogen due to the strong electron-withdrawing effects of the fluorine atoms, and is in agreement with the general difficulties associated with removal of a DMB group from the related phthalimides and maleimide rings . Fortunately, the desired α,α-difluorohomophthalimide 10 could be readily prepared in 88% isolated yield by the reaction of aryl bromide 9 with 3 equiv of bromozinc-α,α-difluoroacetate 3 and 0.8 equiv of CuBr at room temperature.…”

Application of a Dual Linker with a Reference Cleavage Site in the Identification of a Side Product in the Mitsunobu Transformation of Polymer-Supported Alcohols to Amines

“…The cleaved sample was analyzed by LC/MS. In addition to the expected phthalimide derivative 3 (phthalimide is not cleaved from the HMPB linker under these conditions), we detected an additional component. The side-product was isolated by semipreparative high-performance liquid chromatography (HPLC).…”

Synthesis of Functionalized 6-Hydroxy-2-oxindole Derivatives by Phenoxide Cyclization

“…Next, in order to show the utility of these oxindoles in total synthesis or any other methodology applications, we prepared the N-deprotected oxindoles 5 and 6 using TFA in anisole. 13 Interestingly, in the case of the alkylidene oxindole 2b deprotection using TFA in anisole, the anisole added product 6 was obtained in low yield (Scheme 5).…”