Use of some aryl and heteroaryl nitrilimines and nitrones in the synthesis of spiroheterocycles

✍ Scribed by Eva Jedlovská; Lubor Fišera

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2004
• Tongue: English
• Weight: 142 KB
• Volume: 41
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570410504

✦ Synopsis

Abstract

1,3‐Dipolar cycloadditions of C‐(5‐nitro‐2‐furyl)‐N‐methyl nitrilimine (2a), C‐(5‐nitro‐2‐furyl)‐N‐phenyl nitrilimine (2b), C‐4‐nitrophenyl‐N‐methyl nitrilimine (2c) and C,N‐diphenyl nitrilimine (2d) with 1‐R‐substituted 3,3‐methylene‐5,5‐dimethylpyrrolidin‐2‐ones (1a‐d) where R is H, acetyl, 1,1‐dimethylethoxycarbonyl and 1‐methylethenyl proceed with complete regioselectivity in good yields to afford 1,3,7‐trisubstituted‐6‐oxo‐8,8‐dimethyl‐1,2,7‐triazaspiro[4,4]non‐2‐enes (5a‐g) exclusively. Cycloaddition of C‐(5‐nitro‐2‐furyl)‐N‐phenylnitrone (3b) to the exocyclic double bond of the dipolarophile 1a proceeds to 2‐phenyl‐3‐(5‐nitro‐2‐furyl)‐6‐oxo‐8,8‐dimethyl‐1‐oxa‐2,7‐diazaspiro[4,4]nonane (7) with complete regio‐ and stereoselectivity.