D. Damour et al., cis- and trans-3-(3-indolyl)proline derivatives as conformationally restricted analogues of tryptophan, SYNLETT, (6), 1999, pp. 786-788
A method for the diastereoselective generation of 3-indolyl-3-proline deriv
atives has been developed. The [3+2] cycloaddition reaction of 3-vinylindol
es with dimethyl N-ethoxycarbonyl-N-methoxymethylaminomalonate in the prese
nce of TiCl4, afforded the title compounds after acid hydrolysis and decarb
oxylation reactions. These new amino acids may be viewed as conformationall
y restricted mimetics of tryptophan.