Brønsted Acid-Catalyzed, Highly Enantioselective Addition of Enamides to In Situ<i>-</i>Generated<i>ortho</i>-Quinone Methides: A Domino Approach to Complex Acetamidotetrahydroxanthenes
作者:Satyajit Saha、Christoph Schneider
DOI:10.1002/chem.201406044
日期:2015.2.2
The highly enantioselective conjugate addition of enamides and enecarbamates to in situ‐generated ortho‐quinone methides, upon subsequent N,O‐acetalization, gives rise to acetamido‐substituted tetrahydroxanthenes with generally excellent enantio‐ and diastereoselectivities. A chiral BINOL‐based phosphoric acid catalyst controls the enantioselectivity of the carbon–carbon bond‐forming event. The products
cycloaddition of β-substituted ene- and thioenecarbamates as well as cyclic enamides with quinone diimides catalyzed by a BINOL- and SPINOL-derived phosphoric acid is reported. A wide variety of 2,3-disubstituted 2-aminoindolines, including polycyclic ones, were prepared in generally high yields (up to 98%) with moderate to complete diastereoselectivities and in most cases excellent enantioselectivities
Trimethylchlorosilane-promoted aza-Mannich reaction of enecarbamates and aldimines
作者:Pengcheng Wu、Deqin Lin、Xiaoxia Lu、Li Zhou、Jian Sun
DOI:10.1016/j.tetlet.2009.09.097
日期:2009.12
A trimethylchlorosilane-promoted aza-Mannich reaction is reported utilizing enecarbamates as the nucleophile and aromatic N-Boc aldimines as the electrophile. A variety of nucleophiles and electrophiles are tolerated by the reaction conditions, delivering the adduct products in excellent yields with high E-stereoselectivities. (C) 2009 Elsevier Ltd. All rights reserved.