An unusual reaction of a Reissert compound involving alkylation, rearrangement, SNAr and SET processes

Abstract

Reaction of isoquinoline Reissert compound 1 with NaH and then isopropyl iodide in DMF at 22 °C led to four isolated products. Ketone 3 is the expected product of the well-known rearrangement of the intermediate Reissert anion. Cyano lactam 4 results from SNAr intramolecular displacement of the fluoride ion from the activated aroyl moiety of the anion. Isopropyl lactam 5 is proposed to result from a SET (single electron transfer) process via formation of the radical anion of 4, subsequent loss of the cyanide ion, and coupling of the resultant radical with isopropyl radicals formed via copper used to “stabilize” the alkyl iodide. The expected alkylated product 2 is also formed via a SET process involving electron transfer from the Reissert anion to 4, leading to the Reissert radical. Use of “non-stabilized” bromide or iodide led to 3 and 4, but did not produce 2 or 5.