SynopsisVapor phase photografting of monomer mixtures on low-density polyethylene film, on which benzoyl peroxide is coated, was investigated at 60°C using various vinyl, allyl, and solid monomers. Styrene (St) itself was difficult to graft on the film substrate, but the combinations of St with vinyl monomers such as acrylonitrile (AN), glycidyl methacrylate (GMA), acrylic acid, and methacrylic acid led to the accelerated grafting, affording a maximum percent grafting at an certain monomer ratio. The same combination effect was observed for AN-N-vinyl pyrrolidone and -GMA monomer mixtures. The monomer combinations such as allyl aldehyde-St and allyl alcohol-maleic anhydride were useful for performing the grafting of allyl monomers effectively. Maleic anhydride and maleimide as solid monomers were also possible to introduce into the film substrate by means of the monomer combination, where St, N-vinyl pyrrolidone, vinyl ethers, and benzyl methacrylate were available as comonomers. Thus, the monomer combinations affording an accelerating effect on grafting may be monomer pairs rich in an alternative copolymerizability, suggesting that monomer reactivity ratio controls a major factor for the combination effect. It was confirmed from IR study on grafted films that both monomer components are introduced in the film substrate as the grafted chain component.

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The stereoselective total synthesis of (−)-12,13-epi-obtusenyne is described. The oxonene skeleton possessing cis-orientated alkyl substituents at the α,α′-positions to ether linkage was stereoselectively constructed via cyclization of the corresponding hydroxy epoxide promoted by Eu(fod)3.

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