Intramolecular reaction

About: Intramolecular reaction is a research topic. Over the lifetime, 5015 publications have been published within this topic receiving 138213 citations.

Aza-Morita-Baylis-Hillman reactions and cyclizations of conjugated dienes activated by sulfone, ester, and keto groups.

Abstract: The aza-Morita−Baylis−Hillman reactions of aldimines 2 with several activated conjugated dienes were found to proceed smoothly in DMF in the presence of 3-hydroxyquinuclidine (HQD). Imines 2 reacted with 1-(p-toluenesulfonyl)-1,3-butadiene (3), methyl 2,4-pentadienoate (6), hexa-3,5-dien-2-one (7), and 1-phenylpenta-2,4-dien-1-one (8) to afford adducts 4, 13, 14, and 15, respectively. While products 4, 13, and 15 were formed as E,Z mixtures, adducts 14 were obtained as essentially pure E-isomers. Cyclization of the E-isomers of the products derived from the dienyl sulfone 3 and the dienoate ester 6 occurred via intramolecular conjugate addition under base-catalyzed conditions to afford functionalized piperidines 5 and 16, respectively. The aza-Morita−Baylis−Hillman reaction and subsequent cyclization of the imine 2a with 3 were also carried out as a one-pot reaction, while the reaction mixture was simultaneously irradiated at 300 nm to effect the photoisomerization of the unreactive Z-adduct of the corres...

Copper/Silver-Cocatalyzed Conia−Ene Reactions of 2-Alkynic 1,3-Dicarbonyl Compounds

Abstract: A copper/silver-catalyzed Conia−ene reaction has been developed for selectively constructing five-membered and six-membered rings. In the presence of (CuOTf)2·C6H6 and AgBF4, a variety of 2-alkynic 1,3-dicarbonyl compounds underwent the Conia−ene intramolecular reaction smoothly in moderate to good yields. It is noteworthy that both 2-phenylacetylhept-6-ynenitrile and diethyl 2-(pent-4-ynyl)malonate are also suitable substrates under the standard conditions, and the selectivity toward endo- or exo-products depends on the substitutents at the terminal of alkynes.

Efficient intramolecular 2+2 photocycloaddition of styrene derivatives toward cyclophanes

Abstract: The formation of 1,2-diphenylcyclobutane by the photocyclodimerization of styrene has opposing demands with regard to the styrene concentration: the first dimerization step with a short-lived active species needs high concentration of styrene, whereas the second cyclization step requires dilute conditions to avoid intermolecular side reactions. In order to overcome this monomer concentration effect by constraining the reactants into a single molecule, ..cap alpha..,omega-bis(vinylaryl)alkanes were treated under photoirradiation, which successfully afforded cyclophanes having cis disubstituted cyclobutane ring(s). The results are summarized.