Triethylamine Enables Catalytic Generation of Oxidopyrylium Ylides for [5+2] Cycloadditions with Alkenes: An Efficient Entry to 8-Oxabicyclo[3.2.1]octane Frameworks
作者:Yasunori Toda、Masahiro Shimizu、Taichi Iwai、Hiroyuki Suga
DOI:10.1002/adsc.201800290
日期:2018.6.15
of 8‐oxabicyclo[3.2.1]octane derivatives including synthetic intermediates of natural products is described, in which triethylamine effectively catalyzes [5+2] cycloaddition reactions between oxidopyrylium ylides and alkenes. This method can be applied not only to intermolecular cycloadditions with various alkenes but also to intramolecular cycloadditions. The key finding is that the combined use of
Ozonolytic Cleavage of 3-Oxidopyrilium Betaine-Derived Cycloadducts: Simple and Efficient Access to Stereodefined Tetrahydrofurans
作者:Colin W. Fishwick、Glynn Mitchell、Peter F. Pang
DOI:10.1055/s-2004-837202
日期:——
A range of bicyclic allylic alcohols, obtained from the highly stereoselective reduction of endo-adducts derived from [3+2] cycloaddition of 3-oxidopyrilium betaine to various olefins, undergo efficient ozonolytic cleavage followed by reduction to yield stereodefined tetrahydrofurans in high overall yields as single diastereoisomers.
A Practical Approach to Stereochemically Defined Tetrahydrofurans from [5+2] Oxidopyrylium-Alkene Cycloadducts
作者:Girish Trivedi、Manikrao Salunkhe、Arun A. Yadav、Prajakta Sarang
DOI:10.1055/s-2007-973866
日期:2007.4
The feasibility of the Beckmann fragmentation reaction has been extended to [5+2] cycloadducts derived from the cycloaddition of 3-oxidopyrylium betaine to various olefins. Upon cleavage, these cycloadducts give stereochemically defined tetrahydrofurans in high overall yields as single diastereoisomers.
Sammes, Peter G.; Street, Leslie J., Journal of the Chemical Society. Perkin transactions I, 1983, p. 1261 - 1266
作者:Sammes, Peter G.、Street, Leslie J.
DOI:——
日期:——
Silica gel enables Achmatowicz rearrangement with KBr/oxone under “anhydrous” condition for one-pot functionalization
作者:Guodong Zhao、Rongbiao Tong
DOI:10.1016/j.tet.2018.12.022
日期:2019.3
Silica gel was found to effectively promote Achmatowiczrearrangement (AchR) using KBr/oxone under near anhydrous condition. This new protocol allows direct functionalization of AchR products in a one-pot manner, effectively reducing the cost, time, and environmental impacts derived from the conventional stop-and-go approach using separate reaction vessels. These advantages were demonstrated in four