Diamidophosphites with remote P∗-stereocentres and their performance in Pd-catalyzed enantioselective reactions

Diamidophosphite ligands based on 1,1′-bis(hydroxymethyl)ferrocene or N1,N2-bis((S)-1-hydroxy-3,3-dimethylbutan-2-yl)oxalamide and bearing 1,3,2-diazaphospholidine rings with stereogenic phosphorus atoms were obtained. The use of these ligands provides up to 96% ee in Pd-catalyzed asymmetric allylations of (E)-1,3-diphenylallyl acetate, up to 70% ee in Pd-catalyzed desymmetrizations of N,N′-ditosyl-meso-cyclopent-4-ene-1,3-diol bis-carbamate and up to 80% ee in Pd-catalyzed allylic alkylations of cinnamyl acetate with ethyl 2-oxocyclohexane-1-carboxylate. Results obtained with a diamidophosphite containing an oxalamide framework show the considerable potential of such ligands in enantioselective catalysis.

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1,1′-Bis[((2R,5S)-3-phenyl-1,3-diaza-2-phosphabicyclo[3.3.0]octyloxy)methyl]ferroceneC34H40FeN4O2P2Ee = 100%[α]D25 = −284.8° (c 1.0, CHCl3)Source of chirality: (S)-Glutamic acidAbsolute configuration: (SC,RP)

N1,N1-Bis[((2R,5S)-3-phenyl-1,3-diaza-2-phosphabicyclo[3.3.0]octyloxy)-3,3-dimethylbutan-2-yl]oxalamideC34H54N6O4P2Ee = 100%[α]D25 = +284.5° (c 1.0, CHCl3)Source of chirality: (S)-Glutamic acid and (S)-tert-leucinAbsolute configuration: (SC,SC,RP)