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.
Reductive Studies on 3-Oxidopyrylium-alkene [5 + 2] Cycloadducts: Access to Some Hydroxy Cycloheptenoids
作者:Arun A. Yadav、Urlam Murali Krishna、Prajakta S. Sarang、Prashant S. Patil、Girish K. Trivedi、Manikrao M. Salunkhe
DOI:10.1080/00397911.2010.481754
日期:2011.4.5
Abstract The scope of nickelboride as a versatile reducing reagent is extended to the 3-oxidopyrylium-alkene [5 + 2] cycloadducts. In this report, we demonstrate that nickelboride is capable of one-pot 1,2- and 1,4-reduction of enones present in the cycloadducts in good yields. Subsequent elaboration of the cycloadducts towards synthesis of functionalized cycloheptenoid derivatives devoid of the oxa-bridge