Reactivity of [60]Fullerene with Primary Nitro Compounds: Addition or Catalysed Condensation to Isoxazolo[60]fullerenes1. Issue 35 (29th October 2014)

• Record Type: Journal Article
• Authors: Biagiotti, Giacomo; Cicchi, Stefano; De Sarlo, Francesco; Machetti, Fabrizio
• Is Part Of: European journal of organic chemistry. Issue 35(2014)
• Page Start: 7906
• Page End: 7915
• Publication Date: 2014-10-29
• Subjects: Cycloaddition -- Condensation reactions -- Fullerenes -- Copper -- Nitro compounds; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201402990
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: The catalysed condensation of [60]fullerene with ethyl nitroacetate (1b ) or analogous activated nitro derivatives to afford isoxazolino[60]fullerenes has been achieved in both homogeneous and heterogeneous conditions. This direct synthetic approach is more convenient than previous methods. Model reactions with electron‐poor dipolarophiles led to either condensation to isoxazolines or to conjugate addition products, depending on the nitro compound and catalyst. The former product was favoured by the use of Cu II in the catalytic system. Conversely, [60]fullerene underwent catalytic condensation, even in the absence of copper(II) salts, only with activated nitro compounds and addition only with nitroalkanes in excess base. Note, the formal conjugated fullerene addition product was obtained in isomeric form, as previously reported. A possible explanation is presented for this contrasting behaviour. Abstract : Isoxazolino[60]fullerenes have been synthesised directly from activated nitro compounds by a catalytic process (DABCO or NMP/[Cu]). The protocol is simple, versatile and tolerant towards diverse functional groups. A mechanism is proposed to explain both this condensation and the known addition with nitroethane in excess base.