Stereoselective Synthesis of Secondary and Tertiary Boronic Esters via Matteson Homologation
作者:Markus Tost、Uli Kazmaier
DOI:10.1021/acs.orglett.3c02360
日期:2023.9.22
esters with lithium dichlorocarbenoids and various nucleophiles proved to be a useful method for the synthesis of functionalized polyketides in a highlystereoselective fashion. Via repeated homologation steps, only 1,2-anti- and 1,3-syn-configured products were obtained. Homologation with substituted carbenoids followed by reaction with carbon nucleophiles resulted in configurationally inverted products
Preparation of lithium stannide mixtures in organic solvents. A alternate source of lithium in organolithium chemistry
作者:Reuben D. Rieke、Jun-sik Lee、Young-Sik Kye、Gerard S. Harbison
DOI:10.1016/j.jorganchem.2004.04.037
日期:2004.10
Lithium stannides were prepared from lithium naphthalenide and tin (II) chloride or tin (0) powder in THF solvent at room temperature under dry argon atmosphere. They were characterized with elemental analysis, XRD, and solid Li-6.7 NMR. Stabilities and reactivities of lithium stannides prepared from different conditions were tested and showed they were stable for a limited time at low temperatures. Best reactivity was obtained when they were prepared from tin (II) chloride and an excess of lithium naphthalenide. The lithium stannide mixture can reductively cleave carbon-halogen bonds and yield pinacol coupling with aldehydes. Organolithium compounds prepared from lithium stannides and organic halides add to ketones or aldehydes under Barbier conditions. (C) 2004 Published by Elsevier B.V.