Gold(I)-catalyzed double migration cascades toward (1E,3E)-dienes and naphthalenes
作者:Alexander S. Dudnik、Todd Schwier、Vladimir Gevorgyan
DOI:10.1016/j.tet.2008.10.109
日期:2009.2
A novel gold(I)-catalyzed cascade cycloisomerization of a variety of propargylic esters leading to unsymmetrically substituted naphthalenes has been developed. This domino process involves an unprecedented tandem sequence of 1,3- and 1,2-migrations of two substantially different migrating groups. It is believed that this transformation proceeds via formation of 1,3-diene intermediate or its equivalent
simple dibenzyl diselenide was found to be the best pre‐catalyst for Baeyer–Villigeroxidation of (E)‐α,β‐unsaturated ketones with the green oxidant hydrogen peroxide at room temperature. The organoselenium catalyst used in this reaction could be recycled and reused several times. This new method was suitable not only for methyl unsaturated ketones, but also for alkyl and aryl unsaturated ketones.
Gold(I)-catalyzed synthesis of (1E,3E)-dienes from propargylic esters
作者:Alexander S. Dudnik、Todd Schwier、Vladimir Gevorgyan
DOI:10.1016/j.jorganchem.2008.08.010
日期:2009.2
A mild and stereoselective gold(I)-catalyzed domino transformation of propargylicesters leading to substituted (1E,3E)-dienes has been developed. This cascade process proceeds via a sequence of 1,3-acyloxy- or 1,3-phosphatyloxy migrations to form allenic intermediate followed by a proton transfer.
已经开发了一种温和且立体选择性的金 (I) 催化的炔丙酯的多米诺转化,导致取代的 (1 E ,3 E )-二烯。该级联过程通过一系列 1,3- 酰氧基或 1,3- 磷脂酰氧基迁移形成丙二烯中间体,然后进行质子转移。
Hydrolyzed ethylene vinyl acetate polymer and microcapsule
申请人:CAPSULATED SYSTEMS, INC.
公开号:EP0067021A1
公开(公告)日:1982-12-15
Partially hydrolyzed ethylene-vinyl ester copolymers are disclosed prepared by alcoholysis of, for example, ethylene-vinyl acetate copolymer using 4 to 9 times the amount of alcohol stoichiometrically required to achieve a predetermined hydrolysis degree. Also disclosed is a process for forming microcapsules by coacervation of the aforesaid copolymers and highly impervious microcapsules prepared therefrom.
Thermoplastic core-shell compositions having a rigid core, a rubbery acrylic shell and transition layer intermediate between the core and shell layers and formed of the core and shell monomer components have excellent elastomeric properties. Although the rigid and rubbery components include interreactive functional monomers, the resulting elastomers remain thermally processable in extrusion and injection molding equipment.