Anionic Cascade Reaction Followed by Silylative Dieckmann Cyclization: A Straightforward Route to Tricyclic Fused Ring Systems Starting from Alkynyl Esters Tethered to Bicyclo[n.2.0]alkanones
The successive addition of sodiumethoxide and TBSOTf (or TMSOTf) to alkynyl esters tethered to bicyclo[n.2.0]alk-anones (n = 3-5) promoted a domino anionic reaction and a Dieckmann condensation, respectively, which led to 5-6-5, 6-6-5, and 7-6-5 tricyclic fused ring systems. These systems represent relevant substructures of numerous bioactive compounds.
New cascade reactions starting from acetylenic ω-ketoesters: an easy access to electrophilic allenes and to 1,3-bridgehead ketones
作者:Aurélie Klein、Michel Miesch
DOI:10.1016/s0040-4039(03)01023-2
日期:2003.6
Acetylenic omega-ketoesters bearing a three carbon-carbon bond spacer reacted smoothly with tetra-n-butylammonium fluoride and with potassium tert-butoxide to afford either electrophilic allenes or 1,3-bridgehead ketones, the latter being potentially useful molecules for the synthesis of biologically active compounds like Garsubellin A and Hispidospermidin. (C) 2003 Elsevier Science Ltd. All rialits reserved.