M. Avalos et al., Unexpected formation of beta-lactams and penem isosteres from mesoionics: sequential ring-opening-rearrangement of [3+2] cycloadducts, CHEM COMMUN, (16), 1999, pp. 1589-1590
A novel and simple method has been developed to obtain penem analogs with b
iologically interesting functionalities, which combines aromatic aldehydes
with thioisomunchnones, a readily available class of mesoionic heterocycles
.