| Abstract: | Pyridinium and isoquinolinium ylides ( 7 and 12 ) derived from malonic ester react in an unusual manner with isocyanates giving the new pyridinium ylide ( 9 ) and the new isoquinolinium ylide ( 14 ). C → N Migration of the COOEt group takes place at room temperature, but, at an elevated temperature, reverse N → C migration of the COOEt group proceeds and ylides 9 and 14 are reconverted into the starting ylides 7 and 12 , respectively. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:36–45, 2002; DOI 10.1002/hc.1104 |
