Synthesis of fluorinatedanalogs of some dienic insect sex pherormones through a stereocontrolled Wittig reaction of β-fluorinated aldehydes with the appropriate ω-functionalized ylides is reported. Some features of the 1H and 19F NMR spectra of these analogs are also discussed.
据报道,通过β-氟化醛与适当的ω-官能化的乙炔的立体控制的Wittig反应,合成了一些二齿昆虫性信息素的氟化类似物。还讨论了这些类似物的1 H和19 F NMR光谱的某些特征。
Cyclisation of 1,2-dioxines containing tethered hydroxyl and carboxylic acid functionality: synthesis of tetrahydrofurans and dihydrofuran-2(3H)-ones
作者:Ondrej Zvarec、Thomas D. Avery、Dennis K. Taylor、Edward R.T. Tiekink
DOI:10.1016/j.tet.2009.11.068
日期:2010.1
stereoselective manner and includes improved methods for previously reported carboxylicacid tether cyclisations. Additionally, improved methods for the oxidation of 1,2-dioxines containing tethered alcohols to furnish tethered carboxylicacids are also detailed. Subsequent reduction of the peroxide linkage enables the generation of functionalised tetrahydrofurans and dihydrofuran-2(3H)-ones, which are useful
Enantiospecific synthesis of (-)-tabtoxinine .beta.-lactam
作者:Roland E. Dolle、Chun Sing Li、Riccardo Novelli、Lawrence I. Kruse、Drake Eggleston
DOI:10.1021/jo00027a024
日期:1992.1
A convergent, 10-step synthesis of optically active tabtoxinine beta-lactam [(-)-1] has been described. Key features of the synthetic route include (1) preparation of a new gamma-cation amino acid synthon, (-)-4, and its use as an electrophile (3 --> 11); (2) the one-pot conversion of methyl sulfide 11 to the Cbz-protected amine 12 via stereoselective sulfilimine rearrangement; and (3) chemoselective lactone ring opening in spiro lactam 15a. Synthons (-)-4 and 3 are available on a semipreparative scale.
Asymmetric acetate aldol reactions in connection with an enantioselective total synthesis of macrolactin A
Asymmetric aldol-like reactions of cinnamaldehyde, dienal 3 (fragment C7-C12 of macrolactin A), and dienal 4 (fragment C15-C24) with (i) chiral acetylthiazolidinethione-derived enolates, (ii) chiral boron enolates, and (iii) silyl enolates in the presence of chiral titanium-2,2'-dinaphthol complexes are compared. Use of the thiazolidinethione auxiliary and TiCl4 shows practical advantages; e.g., C5-C12 fragment 7 has been isolated enantiomerically pure in 74% yield. Copyright (C) 1996 Elsevier Science Ltd