Hydantoins fluorous-phase synthesis

Scheme 7.81 Fluorous phase synthesis of N,N -disubstituted hydantoins.

In a related approach from the same laboratory, the perfluorooctylsulfonyl tag was employed in a traceless strategy for the deoxygenation of phenols (Scheme 7.82) [94], These reactions were carried out in a toluene/acetone/water (4 4 1) solvent mixture, utilizing 5 equivalents of formic acid and potassium carbonate/[l,T-bis(diphe-nylphosphino)ferrocene]dichloropalladium(II) [Pd(dppf)Cl2] as the catalytic system. After 20 min of irradiation, the reaction mixture was subjected to fluorous solid-phase extraction (F-S PE) to afford the desired products in high yields. This new traceless fluorous tag has also been employed in the synthesis of pyrimidines and hydantoins. 

Zhang et al. (2006) have reported an advance fluorous synthesis of hydantoin-, piperazinedione-, and benzodiazepinedione-fused tricyclic and tetracyclic ring systems using a sequence of microwave-assisted, fluorous multicomponent reactions (F-MCRs) and fluorous solid-phase extractions (F-SPEs). They used microwave-assisted one pot, three-component [3+2] cycloaddition of azomethine ylides with... 

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