Ir-Catalyzed Enantioselective Formal C–H Conjugate Addition of Pyrrole and Indoles to α,β-Unsaturated Carbonyl Compounds
作者:Takanori Shibata、Mio Sasaki、Masafumi Kojima、Mamoru Ito
DOI:10.1021/acs.orglett.1c03375
日期:2021.12.3
The chiral Ir(I)-catalyzed intermolecular reaction of N-carbamoylpyrrole and indole derivatives with α,β-unsaturated carbonylcompounds such as crotonates proceeded with high enantioselectivity. The obtained chirally functionalized pyrroles and indoles are formal C–H conjugate adducts. The reaction mechanism was studied by deuterium labeling experiments.
Asymmetric Sulfa-Michael Addition of α,β-Unsaturated Esters/Amides Using a Chiral N-Heterocyclic Carbene as a Noncovalent Organocatalyst
作者:Jiean Chen、Yong Huang、Pengfei Yuan、Sixuan Meng
DOI:10.1055/s-0035-1561843
日期:——
We report an asymmetric sulfa-Michael reaction of α,β-unsaturated amides and estersusing a chiral N-heterocyclic carbene as the HOMO-raising organocatalyst. We discovered an interesting correlation between 13C NMR shifts of substrates and ee of their products. More electron-deficient Michael acceptors afforded higher enantioselectivity.
我们报告了使用手性 N-杂环卡宾作为 HOMO 提升有机催化剂的 α,β-不饱和酰胺和酯的不对称磺胺-迈克尔反应。我们发现底物的 13C NMR 位移与其产物的 ee 之间存在有趣的相关性。更多缺电子迈克尔受体提供更高的对映选择性。
Enantioselective Cross-Coupling of Electron-Deficient Alkenes via Ir-Catalyzed Vinylic sp<sup>2</sup> C–H Alkylation
作者:Takanori Shibata、Masafumi Kojima、Sahoko Onoda、Mamoru Ito
DOI:10.1021/acs.orglett.1c02823
日期:2021.11.5
A chiral Ir-catalyzed reaction of α-aryl-α,β-unsaturatedamides with β-substituted acrylates proceeded to give formal conjugate adducts in high yield and ee (up to 99% yield and up to 95% ee). This is the first example of the enantioselective cross-coupling of two different electron-deficient alkenes via vinylic sp2 C–H activation, and polyfunctionalized chiral compounds were obtained.
A carboxamide can be produced in a high yield by a method for producing a carboxamide, for example, represented by formula (4) :
(wherein R1 and R3 are as defined below), the method comprising a step of allowing a carboxylic acid ester represented by formula (1):
(wherein R1 represents an optionally substituented C1-C20 hydrocarbon group or an optionally substituented C3-C20 heterocyclic group, and R2 represents an optionally substituented C1-C20 hydrocarbon group), an amine represented by formula (2):
R3-NH2 (2)
(wherein R3 represents a hydrogen atom or an optionally substituented C1-C20 hydrocarbon group),
and a formamide compound represented by formula (3):
(wherein R3 is as defined above)
to react in the presence of a metal alkoxide.
Na2CO3-Catalyzed O-Acylation of Phenols for the Synthesis of Aryl Carboxylates with Use of Alkenyl Carboxylates
作者:Xiao-Yu Zhou、Xia Chen
DOI:10.1055/s-0037-1610265
日期:2018.10
phenol and its derivatives has been developed. The procedure provides an efficient catalysis system for the preparation of aryl carboxylates with alkenyl carboxylates as acyl reagents. The reaction proceeded smoothly by using Na2CO3 as the catalyst in MeCN to produce the corresponding aryl carboxylates in good to excellent yields.