title: [4 + 2] cycloadditions of nitroalkenes in water. Highly asymmetric synthesis of functionalized nitronates.
abstract: The [4 + 2] cycloadditions of (E)-2-aryl-1-cyano-1-nitroalkenes 1 with achiral and enantiopure vinyl ethers 2 and 3 carried out in sole water are reported. These reactions occur in a heterogeneous phase under mild conditions and are fast and highly stereoselective. By using (-)-N,N-dicyclohexyl-(1S)-isoborneol-10-sulfonamide as a chiral auxiliary, the cycloadditions are totally asymmetric. The face selectivity is discussed in terms of the shape of the chiral auxiliary and the reactive conformation of vinyl ether.
authors: Dipartimento di Chimica, Università di Perugia, Via Elce di Sotto, 8 I-06123 Perugia, Italy. frifra@unipg.it
authors: F
authors: F
authors: Fringuelli
authors: M
authors: M
authors: Matteucci
authors: O
authors: O
authors: Piermatti
authors: F
authors: F
authors: Pizzo
authors: M C
authors: MC
authors: Burla