the corresponding tetrasubstituted derivatives in good yields (45-68 %). Unfortunately, the final deprotection step leading to the desired chelating compounds was unsuccessful. The replacement of the methyl group by the bulky allyl group afforded only the di- and trisubstituted a 4 atropoisomer in 17 and 50 % yields, respectively. Due to steric reasons, no trace of the tetrasubstituted a 4 atropoisomer