Chiral GAP catalysts of phosphonylated imidazolidinones and their applications in asymmetric Diels–Alder and Friedel–Crafts reactions
作者:Shuo Qiao、Junming Mo、Cody B. Wilcox、Bo Jiang、Guigen Li
DOI:10.1039/c6ob02801b
日期:——
The design and synthesis of recyclable imidazolidinone catalysts using GAP chemistry/technique was described. Their applications in asymmetric Diels–Alder and Friedel–Crafts reactions with α,β-unsaturatedaldehydes resulted in excellent yields and higher enantioselectivities than previous processes. As recyclable small molecular catalysts, phosphonylated imidazolidinones can be recovered and reused
描述了使用 GAP 化学/技术设计和合成可回收咪唑啉酮催化剂。它们在与 α,β-不饱和醛的不对称 Diels-Alder 和 Friedel-Crafts 反应中的应用比以前的工艺产生了优异的产率和更高的对映选择性。作为可回收的小分子催化剂,膦酰化咪唑啉酮可以回收并重复使用最多三次,而不会导致催化活性显着下降。
Immobilization of MacMillan Imidazolidinone as Mac-SILC and its Catalytic Performance on Sustainable Enantioselective Diels-Alder Cycloaddition
(Mac‐SILC) in the pores of silica gel with the aid of an ionic liquid – 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide. The heterogenized organocatalyst was utilized for the enantioselectiveDiels–Alder reaction of cyclopentadiene and cinnamaldehyde, recovered by simple filtration and subsequent evacuation, and repeatedly used up to six times in 81% average chemical yield, 87% ee for endo‐
The development of a new class of hydrazide type organocatalyst, (4R,5R)-1,3-bis(isopropylamino)-4,5-dihenylimidazolidin-2-one 2a, for enantioselective DielsâAlder reactions between cyclopentadiene and α,β-unsaturated aldehydes are presented. The new organocatalyst 2a promoted the reaction, affording DielsâAlder adducts in good yields with good levels of enantioselectivity.
The development of highly active acyclic chiral hydrazides for asymmetric iminium ion organocatalysis
作者:Eoin Gould、Tomas Lebl、Alexandra M. Z. Slawin、Mark Reid、Tony Davies、Andrew D. Smith
DOI:10.1039/c3ob41719k
日期:——
Double asymmetric induction has been employed as a tool to optimise pyrazolidinone-derived organocatalysts for the asymmetric iminiumion catalysed Diels–Alder reaction. Mechanistic studies revealed a superior hydrazide catalyst deriving from methanolysis of the chiral pyrazolidinone precursor. This catalyst displays unusually high endo diastereoselectivity and good enantioselectivity with a range