Rapid and Stereoselective Synthesis of Spirocyclic Ethers via the Intramolecular Piancatelli Rearrangement
作者:Leoni I. Palmer、Javier Read de Alaniz
DOI:10.1021/ol303263q
日期:2013.2.1
The first example of a Piancatelli rearrangement of alcohols is demonstrated utilizing dysprosium(III) triflate as a catalyst to access oxaspirocycles in a highly diastereoselective manner. The cascade reaction constructs the spirocyclicether ring system and the tertiary stereocenter in a single operation and is experimentally easy to perform.
Diastereoselective Reductive Ring Expansion of Spiroketal Dihydropyranones to <i>cis</i>-Fused Bicyclic Ethers
作者:Liangyu Zhu、Liyan Song、Rongbiao Tong
DOI:10.1021/ol302813e
日期:2012.12.7
A novel double cascade synthetic strategy was developed for the diastereoselective syntheses of cis-fused bicyclicethers, featuring cascade Achmatowicz rearrangement/spiroketalization and cascade spiroketal reduction/oxa-Michael cyclization. Especially, the chemo-, regio-, and diastereoselective reduction of densely functionalized spiroketal dihydropyranones, followed by oxa-Michael cyclization in