Sequences of nine and four steps were designed to yield two tirobifan relat
ed macrocycles by SN2 macrocyclization. The cyclic compounds contain the am
ino acid tyrosine, one insaturation and are either 18- or 20-membered rings
. All the reaction conditions are very mild and the overall yields indicate
that the results depend a lot on the structure of the targets and on the l
ength of the reaction sequence. (C) 2000 Published by Elsevier Science Ltd.