Application of directed metalation in synthesis. Part 8: Interesting example of chemoselectivity in the synthesis of thioaurones and hydroxy ketones and a novel anionic ortho-Fries rearrangement used as a tool in the synthesis of thienopyranones and thiafluorenones
摘要:
Chemoselective synthesis of thioaurones or 3-hydroxy benzo[b]thiophen-2-aryl ketones, 1-hydroxy naphtho[2,1-b]thiophen-2aryl ketones and chalcones from N,N-diethyl-ortho-methyl sulfanyl aryl amides were described. (Benzo[b]thiophen-2-yl) alkylates and (naphtho[2, 1-b]thiophen-2-yl) alkylates undergo a novel anionic ortho-Fries rearrangement leading to (3-hydroxy benzo[b]thiophen-2-yl) and (1-hydroxy naphtho[2, 1 -b]thiophen-2-yl) alkyl ketones. The hydroxy ketones were used as intermediates in the synthesis of wide range of benzothienopyranones and thiafluorenones. (c) 2005 Elsevier Ltd. All rights reserved.
Dilithiated synthons of tertiary benzamides, phthalamides, and 0,0′-aryl dicarbamates
作者:R.J. Mills、R.F. Horvath、M.P. Sibi、V. Snieckus
DOI:10.1016/s0040-4039(00)98418-1
日期:1985.1
Dilithiated species 1, 2, and 3, generated by metal-halogenexchange and directed ortho metalation, undergo reaction with electrophiles to afford, in high yield, polysubstituted aromatics 6, 7, and 8 respectively; 9 is formed via a bis anionic Fries rearrangement of 3.
Application of Directed Metallation in Synthesis, Part 2: An Expedient Synthesis of Methoxybenzo[b]thiophenes
作者:Chandrani Mukherjee、Asish De
DOI:10.1055/s-2002-19752
日期:——
A short, simple and expedient synthesis of substituted benzo[b]thiophenes involvingdirected ortho lithiation-side-chain deprotonation-cyclisation-reduction is described. This method is a valuable improvement over earliersyntheses of the same class of compounds, both with respect to the number of steps and overall yields.