K. Undheim et J. Efskind, Ru(II)-catalyzed ring closing metathesis in stereoselective spiroannulations and cascade reactions of cyclic dipeptide substrates, TETRAHEDRON, 56(28), 2000, pp. 4847-4857
Several Ru(II)-catalyzed ring closing metathesis (RCM) reactions have been
reviewed where the substrates were diene or enyne geminally disubstituted c
yclic dipeptide derivatives. The RCM reactions are highly useful for the pr
eparation of spiroannulated cyclic dipeptides as precursors for conformatio
nally restricted cyclic alpha-amino acid derivatives. Five-, six- and seven
-membered rings can be formed. Six- and seven-membered rings were formed mo
st readily from dienes, five- and six-membered rings from enynes. Cascade r
eactions of diene substrates, which were connected by an alkynyl bridge bet
ween the two cyclic dipeptide units, yielded bis(cyclic alpha-amino acid) a
s precursors for cystine analogues. (C) 2000 Published by Elsevier Science
Ltd.