Dual Amine and Palladium Catalysis in Diastereo- and Enantioselective Allene Carbocyclization Reactions
摘要:
A pyrrolidine and Pd catalyzed diastereoselective carbocyclization of aldehyde and ketone-linked allenes has been developed. The cooperative organo/metal-catalyzed cyclization reaction, which presumably proceeds via an enamine intermediate, is efficient and broad in scope. Also, it has been extended to a catalytic asymmetric variant using diarylprolinol-based organocatalysts to afford substituted cyclopentane and pyrrolidine reaction products in up to 82% ee.
Titanium(III)-induced intramolecular radical cyclization of epoxyallene ethers: an efficient method for synthesis of multifunctional tetrahydrofurans
作者:Lubin Xu、Xian Huang
DOI:10.1016/j.tetlet.2007.11.097
日期:2008.1
Ti(III)-mediated intramolecular free radical cyclization of epoxyallene ethers in an exo-mode was studied. The reaction afforded an efficient and highly regioselective method of synthetically important 3-vinyl-4-hydroxymethyl tetrahydrofurans.