Regiospecific synthesis of polysubstituted furans from silylated furans: Expedient syntheses of rosefuran
作者:Ming Keung Wong、Chun Yip Leung、Henry N.C. Wong
DOI:10.1016/s0040-4020(97)00083-5
日期:1997.3
Our approach uses as the key theme trimethylsilyl groups as both blocking groups as well as ipso-directing groups. The advantage of this program is aptly illustrated by two expedient syntheses of rosefuran (9c).
The reactions of bis (trimethylsilyl) peroxide with alkyl, vinyl, alkynyl, aromatic and heteroaromatic anions are described. Depending on the reaction conditions, the trimethylsilyloxy derivatives can be obtained alone or together with the corresponding trimethylsilyl derivatives, which is sometimes the major product. Enolates, generated using magnesium diisopropylamide give the corresponding hydroxycarbonyl
A novel process for producing homopolymers and interpolymers of olefins which involves contacting an olefin and/or an olefin and at least one or more other olefin(s) under polymerization conditions with at least one Ziegler-Natta catalyst comprising a component comprising at least one transition metal and a co-catalyst comprising at least one organometallic compound and at least one compound comprising at least one carbon-oxygen-carbon linkage (C—O—C) of the formula R1—O(—R2—O)m—R3 in amounts sufficient to reduce the electrostatic charge in the polymerization medium. Also disclosed is a process for reducing electrostatic charge in an olefin polymerization medium.