Chiral primary amino alcohol organobase catalysts for the asymmetric Diels–Alder reactions of anthrones with maleimides

Simple chiral triethylsilyl-amino alcohol organocatalysts containing a bulky triethylsilyl group on the oxygen atom at the γ-position were designed and synthesized as new organocatalysts for enantioselective Diels–Alder reactions of anthrones with maleimides to produce chiral hydroanthracene Diels–Alder adducts in up to 99% yield and with up to 94% ee.

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(S)-2-Amino-1,1-diphenyl-3-(diphenylmethylsilyloxy)propanolC28H29NO2Si[α]D20 = −64.8 (c 1.05, CHCl3)Source of chirality: SerineAbsolute configuration: (2S)

(S)-2-Amino-1,1-diphenyl-3-(triphenylsilyloxy)propanolC33H31NO2Si[α]D22 = −55.8 (c 0.52, CHCl3)Source of chirality: SerineAbsolute configuration: (2S)

(S)-2-Amino-1,1-diphenyl-3-(tripropylsilyloxy)propanolC24H37NO2Si[α]D22 = −77.5 (c 1.02, CHCl3)Source of chirality: SerineAbsolute configuration: (2S)

(S)-2-Amino-1,1-diphenyl-3-(trihexylsilyloxy)propanolC33H55NO2Si[α]D24 = −49.6 (c 1.27, CHCl3)Source of chirality: SerineAbsolute configuration: (2S)

(S)-1,1-Diphenyl-3-(triethylsilyloxy)-1-(trimethylsilyloxy)propane-2-amineC24H39NO2Si2[α]D19 = −43.8 (c 1.05, CHCl3)Source of chirality: SerineAbsolute configuration: (2S)

N-Dimethyl-(S)-2-amino-1,1-diphenyl-3-(triethylsilyloxy)propanolC23H35NO2Si[α]D23 = −29.7 (c 0.74, CHCl3)Source of chirality: SerineAbsolute configuration: (2S)

N-Benzyl-(S)-2-amino-1,1-diphenyl-3-(triethylsilyloxy)propanolC28H37NO2Si[α]D24 = −24.8 (c 1.05, CHCl3)Source of chirality: SerineAbsolute configuration: (2S)