Kazuya Kobiro

Complexation between novel cyclophane host and polar guests by hydrogen bonding

Abstract A novel cyclophane host, 2, 11, 20-trihydroxy-2,5,8,11,14,17,20,23,26-nonamethyl [3.3.3]paracyclophane ( 4 ), has been synthesized and found to form complexes with polar organic guest molecules by hydrogen bonding.

Thermal [2+2] cycloaddition of benzene derivative. Cycloaddition of (Z)-[6]paracycloph-3-ene with tetracyanoethylene

Reaction of (Z)-[6]paracycloph-3-ene (1) with tetracyanoethylene gave [2+2] cycloadduct 4 and that with trifluoroacetic acid in methanol afforded 1,4-adduct 8.

Unusual rearrangement of tricyclo[6.3.0.01,4]undecan-5-one

cis,trans-Tricyclo[6.3.0.01,4]undecan-5-one (2) rearranged under acidic conditions through unusual pathways to give cis,cis-tricyclo[6.3.0.01,5]undecan-4-one (3). The application to the α-methylene derivative of 2 afforded the angularly fused triquinane having an α-methylenecyclopentanone unit.

Synthesis of large ring proton cryptate tridecalino [2.2.2] cryptand⊃2hI

Abstract Condensation of 8,9:17,18-didecalino-4,13-diaza-18-crown-6 with 1,8-diiodo-4,5-decalino-3,6-dioxaoctane in the presence of sodium carbonate produced proton cryptate, tridecalino[2.2.2]cryptand⊃2HI.

Unusual reactions of [6](1,4)naphthalenophane and [6](1,4)anthracenophane with dienophiles

[6](1,4)Naphthalenophane ( 1 ) and [6](1,4)anthracenophane ( 2 ) underwent thermal cycloaddition with tetracyanoethylene to give the corresponding [2+2] adducts 3 and 4 . Anthracenophane 2 reacted with dimethyl acetylenedicarboxylate to yield the 1:1 and 1:2 adducts 6 and 7 .

Synthesis and lithium ion selectivity of 14-crown-4 derivatives having bulky subunits: cis and trans isomers of 2-phenylcyclohexano-14-crown-4, 2,3-diphenylcyclohexano-14-crown-4 and 2,3-di-(1-adamantyl)-14-crown-4

cis- and trans-2-Phenylcyclohexano-14-crown-4, cis- and trans-2,3-diphenylcyclohexano-14-crown-4, and cis- and trans-2,3-di-(1-adamantyl)-14-crown-4 have been prepared and their ion selectivities toward alkali metal cations examined by means of the extraction of alkali metal picrates, the measurement of stability constants of the complexes with lithium or sodium perchlorate, and the electrode response potential measurement for the ion-sensitive membranes. The remarkable dependence of the complexation ability to Li+ on the cis/trans stereochemistry of the ionophores is discussed on the basis of their geometries estimated by molecular mechanics calculations and the structures of cis- and trans-diphenylcyclohexano derivatives determined by X-ray structure analyses. In order to assist the discussion, the X-ray structure analyses of the lithium picrate complex of decalino-14-crown-4 and the 2∶1 ‘sandwich-type’ complex of benzo-14-crown-4 with sodium perchlorate have also been undertaken.

Thermal [2 + 2] cycloaddition of (z)-[6]paracycloph-3-ene with tetracyanoethylene

Reaction of (Z)-[6]paracycloph-3-ene (2) with tetracyanoethylene (TCNE) gave a [2 + 2] cycloadduct (4), which represents the first example of thermal [2 + 2] cycloaddition of a benzene derivative under mild conditions. The structure of 4 was confirmed by x-ray crystallographic analysis. Semi-empirical PM3 calculations and the measurement of the He I photoelectron spectrum of 2 indicated that the ionization potential of 2 is considerably lower than that of [6]paracyclophane (1), which gave a [4 + 2] cycloadduct (3) with TCNE. The unusual pericyclic selectivity and regioselectivity are discussed on the basis of PM3 calculations. The regioselectivity is ascribed to the higher ϕ bond order of the bridgehead aromatic bond of 2, which is on the same side of the bridge double bond, than that of the bond on the opposite side of the bridge double bond.