amount of InCl3 and aceticanhydride remarkably promotes the Knoevenagel condensation of a variety of aldehydes and activated methylene compounds. This catalytic system accommodates aromatic aldehydes containing a variety of electron-donating and -withdrawing groups, heteroaromatic aldehydes, conjugate aldehydes, and aliphatic aldehydes. Central to successfully driving the condensation series is the formation
through a cascadereaction between 2‐isocyanoethylindole and alkylidene malonates catalyzed by a chiral N,N′‐dioxide/MgII catalyst. Fused polycyclic indolines containing three stereocenters were afforded in good yields with excellent diastereo‐ and enantioselectivities through a Michael/Friedel–Crafts/Mannich cascade. When 2‐substituted 2‐isocyanoethylindoles were used, spiroindoline derivatives were obtained
Cu-Catalyzed Asymmetric Michael Addition of Glycine Derivatives to α,β-Unsaturated Malonates
作者:Xuelong Hou、Qing Li、Jun Yao、Lixin Dai
DOI:10.1002/cjoc.201090297
日期:2010.9
Michaeladdition of glycine imines with alkylidene and arylidene malonates has been developed using Cu/FcPhox as catalyst, providing corresponding Michael products in high yields with high diastereo‐ and enantioselectivities.
Phosphine-Catalyzed [4+2] Annulations of 2-Alkylallenoates and Olefins: Synthesis of Multisubstituted Cyclohexenes
作者:Yang S. Tran、Tioga J. Martin、Ohyun Kwon
DOI:10.1002/asia.201100190
日期:2011.8.1
From our investigations on phosphine‐catalyzed [4+2] annulations between α‐alkyl allenoates and activated olefins for the synthesis of cyclohexenes, we discovered a hexamethylphosphorous triamide (HMPT)‐catalyzed [4+2] reaction between α‐alkyl allenoates 1 and arylidene malonates or arylidene cyanoacetates 2 that provides highly functionalized cyclohexenes 3 and 4 in synthetically useful yields (30–89 %)
A simple and efficient catalyticasymmetric [small alpha]-addition of isocyanides to alkylidene malonates was realized using a chiral N,N[prime or minute]-dioxide/MgII catalyst. A variety of 2-alkyl-5-aminoxazoles were obtained in up to 99% yield and 96% ee, and could be converted to imides and dipeptides.