F. Fotiadu et al., Efficient synthesis of 3-methylene-2-pyrrolidinone and highly exoselectiveDiels-Alder addition to cyclopentadiene, TETRAHEDR L, 40(5), 1999, pp. 867-870
A new efficient synthesis of 3-methylene 2-pyrrolidinone 1 involving ylide-
lactame 6 is reported. Diels-Alder cycloadditions of 1 to cyclopentadiene e
xhibited very high exoselectivitics, regardless of the experimental conditi
ons. These results confirm the generality of exoselectivity for conformatio
nally restricted s-cis dienophiles and indicate that the dienophile functio
nality and dipole moment have little influence on its magnitude. (C) 1999 E
lsevier Science Ltd. All rights reserved.