| Abstract: | (5S)-1-Benzoyl-3-(E)-cyanomethylidene]-5-(methoxycarbonyl)pyrrolidin-2-one ( 5 ) was prepared in four steps from L -pyroglutamic acid ( 1 ). 1,3-Dipolar cycloadditions of diazomethane ( 6 ) and 2,4,6-trimethoxybenzonitrile oxide ( 7 ) gave substituted 1,2,7-triazaspiro4.4]non-1-en-6-one 12 and 1-oxa-2,7-diazaspiro4,4]non-1-en-6-one 13 in 38 and 20% de, respectively. On the other hand, reaction of 5 with N-phenylbenzonitrile imines 8 and 9 , generated in situ from the corresponding hydrazonoyl chlorides 10 and 11 , respectively, and Et3N, furnished racemic pyrrolo3,4-c]pyrazoles 14 and 15 in 61 and 56% de, respectively. Cycloaddition of nitrile oxide 7 , when performed in the presence of Et3N, led to pyrrolo3,4-d]isoxazole 16 in 85% de. |
