Captodative α,β-unsaturated oxazolines as dienophiles in the asymmetric Diels-Alder reaction
摘要:
Captodative oxazoline derivative 5a gave rise to four-cycloadducts 6,7,8 and 9 in the presence of trifluoroacetic anhydride and cyclopentadiene. Hydrolysis of 6 led to alpha-phenylthio carboxylic acid 14.
The preparation of several oxazolines substituted at C-2 by an hetero substituted methyl group is reported. 2-Aminomethyl, 2-azidomethyl, 2-nitromethyl and 2-hydroxymethyl oxazolines were obtained by substitution of the corresponding 2-halogenomethyl oxazolines. On the other hand, 2-benzyloxycarbonylaminomethyl, 2-thiophenylmethyl, 2-selenophenylmethyl oxazolines were prepared by condensation of the appropriate iminoether with a beta-aminoalcohol.