Synthesis and evaluation of a new non-cross-linked polystyrene supported hydantoin chiral auxiliary for asymmetric aldol reactions

A new non-cross-linked polystyrene supported chiral hydantoin was prepared and it was shown to be a particularly effective chiral auxiliary for asymmetric aldol reactions, affording high yields and excellent diastereoselectivity. Furthermore, the recovery and recycling of the polymer-supported chiral auxiliary have been successfully achieved without an appreciable reduction in the yield or diastereoselectivity.

Figure optionsDownload as PowerPoint slide

(S)-5-(4-Hydroxybenzyl)-3-phenylhydantoinC16H14N2O3[α]D20=-86.7 (c 0.3, CH3COCH3)Absolute configuration: (S)Source of chirality: l-tyrosine methyl ester hydrochloride

(S)-5-(4-(4-Vinylbenzyloxy)benzyl)-3-phenylhydantoinC25H22N2O3[α]D20=-9.3 (c 1.0, CH2Cl2)Absolute configuration: (S)Source of chirality: l-tyrosine methyl ester hydrochloride

(S)-5-(4-(4-Vinylbenzyloxy)benzyl)-3-phenyl-1-propionylhydantoinC28H26N2O4[α]D20=-8.75 (c 0.4, CH2Cl2)Absolute configuration: (S)Source of chirality: l-tyrosine methyl ester hydrochloride

(2S,3S)-3-Hydroxy-2-methyl-3-phenylpropanoic acidC10H12O3[α]D20=-28.8 (c 0.4, CH2Cl2)Absolute configuration: (2S,3S)Source of chirality: chiral auxiliary induced aldol reactions

(2S,3S)-3-Hydroxy-2-methyl-3-(3-nitrophenyl)propanoic acidC10H11NO5[α]D20=-38.0 (c 0.4, CH2Cl2)Absolute configuration: (2S,3S)Source of chirality: chiral auxiliary induced aldol reactions

(2S,3S)-3-(4-Chlorophenyl)-3-hydroxy-2-methylpropanoic acidC10H11ClO3[α]D20=-15.9 (c 0.8, CH2Cl2)Absolute configuration: (2S,3S)Source of chirality: chiral auxiliary induced aldol reactions

(2S,3S)-3-Hydroxy-3-(4-methoxyphenyl)-2-methylpropanoic acidC11H14O4[α]D20=-19.0 (c 0.4, CH2Cl2)Absolute configuration: (2S,3S)Source of chirality: chiral auxiliary induced aldol reactions

(2S,3S)-3-Hydroxy-2-methyl-3-(thiophen-2-yl)propanoic acidC8H10O3S[α]D20=+15.5 (c 0.4, CH2Cl2)Absolute configuration: (2S,3S)Source of chirality: chiral auxiliary induced aldol reactions

(2S,3R)-3-Hydroxy-2-methylhexanoic acidC7H14O3[α]D20=+11.2 (c 0.4, CH2Cl2)Absolute configuration: (2S,3R)Source of chirality: chiral auxiliary induced aldol reactions