Diastereoselective Diels−Alder Reactions of <i>N</i>-Sulfonyl-1-aza-1,3-butadienes with Optically Active Enol Ethers: An Asymmetric Variant of the 1-Azadiene Diels−Alder Reaction
作者:Ryan C. Clark、Steven S. Pfeiffer、Dale L. Boger
DOI:10.1021/ja0571646
日期:2006.3.1
room-temperature asymmetricDiels-Alder reaction of N-sulfonyl-1-aza-1,3-butadienes is reported enlisting a series of 19 enol ethers bearing chiralauxiliaries, with many providing highly diastereoselective (endo and facial diastereoselection) reactions, largely the result of an exquisitely organized [4+2] cycloaddition transition state. Three new, readily accessible, and previously unexplored auxiliaries rationally
Enantioselective [4 + 2] Cycloadditions of <i>o</i>-Quinone Methides: Total Synthesis of (+)-Mimosifoliol and Formal Synthesis of (+)-Tolterodine
作者:Carolyn Selenski、Thomas R. R. Pettus
DOI:10.1021/jo048703c
日期:2004.12.1
The first example of an enantioselectivecycloaddition of an o-quinone methide (o-QM) with a chiral enol ether is described along with the total synthesis of (+)-mimosifoliol and the formal synthesis of (+)-tolterodine. These syntheses exemplify a three-component, one-pot benzopyran approach for the construction of chiral benzylic junctions. Cycloadditions of various enol ethers and o-QMs are examined
Cycloaddition of 2,3,4,5-tetrahydropyridine N-oxide to vinyl ethers. Enantioselective synthesis of 2-(N-benzylpiperidin-2-yl)ethanol
作者:William Carruthers、Peter Coggins、John B. Weston
DOI:10.1039/c39910000117
日期:——
The title compound has been obtained in high optical purity by cycloaddition of 2,3,4,5-tetrahydropyridineN-oxide and (R)-2,2-dimethyl-1-phenylpropyl vinylether followed by N-benzylation and reduction of the salt with lithium aluminium hydride.