An Expedient Phosphine-Catalyzed [4 + 2] Annulation: Synthesis of Highly Functionalized Tetrahydropyridines
Xue-Feng Zhu, Jie Lan and Ohyun Kwon*
*Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, Email: ohyunchem.ucla.edu
X.-F. Zhu, J. Lan, O. Kwon, J. Am. Chem. Soc., 2003, 125, 4716-4717.
Organic phosphine-catalyzed [4 + 2] annulation of ethyl 2-(substituted-methyl)-2,3-butadienoates as 1,4-dipole synthons with N-tosylimines gave ethyl 2,6-cis-disubstituted-1-(4-tosyl)-1,2,5,6-tetrahydro-pyridine-3-carboxylates in excellent yields with complete regioselectivity and high diastereoselectivity.
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