ylides derived from short-chain trialkylphosphines in the Wittig-type olefinationreactions toward the synthesis of alkenes, including stilbenes, styrenes, and 1,3-dienes, as well as reagents for homologation reactions, are described. The methods allow easy access to alkenes with high (E)-stereoselectivity in good yield. These reactions are conducted with weak bases in aqueous media, which allows easy
Alkenes from Terminal Epoxides Using Lithium 2,2,6,6-Tetramethylpiperidide and Organolithiums or Grignard Reagents
作者:David M. Hodgson、Matthew J. Fleming、Steven J. Stanway
DOI:10.1021/ja045513a
日期:2004.10.1
alkenes, dienes, and allylsilanes) are efficiently prepared by alpha-deprotonation of terminal epoxides using lithium 2,2,6,6-tetramethylpiperidide, followed by in situ trapping with organolithiums or Grignardreagents.
The Reactivity of Epoxides with Lithium 2,2,6,6-Tetramethylpiperidide in Combination with Organolithiums or Grignard Reagents
作者:David M. Hodgson、Matthew J. Fleming、Steven J. Stanway
DOI:10.1021/jo070291v
日期:2007.6.1
2-disubstituted epoxides in the presence of LTMP to generate alkenes in a completely regio- and highlystereoselective manner. Arylated alkenes, dienes, allylsilanes, and enynes are accessed using this procedure. The methodology is applied in the synthesis of the roller leaf moth pheromone, (3E,5Z)-dodecadienyl acetate. The corresponding reaction without LTMP has also been examined, and a study using deuterated
AgAsF6 as safe alternative to AgClO4 for generating cationic zirconocene species: Utilities in lewis acid-promoted selective CC bond forming reactions
synthesis, AgAsF6 proved to be an efficient catalyst that serves as a safe alternative to AgClO4. Scope and limitation is discussed on this new catalyst in the processes including (1) alkyl/alkenyl transfer reaction from organozirconocene chloride to aldehyde, (2) two- and four-carbon homologation of aldehyde, (3) dual synthetic methods of 1,3-dienes from aldehydes/ketones via 1,3-bimetallic species
New and highly (E)-selective synthesis of terminal 1,3-diene via three-carbon elongation of aldehyde
作者:Hideki Maeta、Keisuke Suzuki
DOI:10.1016/s0040-4039(00)61102-4
日期:1992.9
A new synthetic method of 1,3-diene by three-carbon elongation of aldehyde is described. 3-Trimethylsilyl-1-propenylzirconocene chloride (2), generated from 3-trimethylsilyl-1-propyne (1) and Cp2Zr(H)Cl, reacts with aldehyde in the presence of catalytic AgClO4 and subsequent one-pot 1,4-elimination affords 1,3-dienes in high yields with excellent (E)-selectivities.