An asymmetric inverse-electron-demandhetero-Diels-Alderreaction between o-quinone methides and azlactones to generate potentially pharmacological active dihydrocoumarins has been achieved efficiently by using a chiral N,N'-dioxide-Sc(III) complex as the catalyst. The desired products were obtained in high yields with excellent enantioselectivities and diastereoselectivities (up to 94% yield, 96%
Asymmetric organocatalytic sulfenylation for the construction of a diheteroatom-bearing tetrasubstituted carbon centre
作者:Qingfa Tan、Qianping Chen、Zitong Zhu、Xiaohua Liu
DOI:10.1039/d2cc03443c
日期:——
construct diheteroatom-bearing carbon centres was achieved by employing chiral guanidine organocatalysts. This protocol provided a facileroute towards the synthesis of α-fluoro-α-sulfenyl-β-ketoamides, azlactone adducts and α-sulfur-substituted amino acid derivatives in high yields with good to excellent enantioselectivities. A possible working mode was proposed to elucidate the chiral control of
COAP-Pd Catalyzed Asymmetric Allylic Alkylation of Azlactones with MBH Carbonates: Access to Unnatural α-Quaternary Stereogenic Glutamic Acid Derivatives
作者:Sheng-Suo Zhou、Xing-Yun Sun、Wen-Kai Liu、Jia-Yu Song、Zheng Wang、Zheng-Hang Qi、Xing-Wang Wang
DOI:10.1021/acs.joc.3c01152
日期:2023.8.18
palladium-catalyzed regioselective and asymmetric allylic alkylation of azlactones with MBH carbonates has been developed with chiral oxalamide-phosphine ligands. The corresponding reaction afforded a range of optically active γ-arylidenyl glutamic acid derivatives bearing an α-chiral quaternarystereocenter in good yields with excellent linear regio- and high enantioselectivity. This protocol furnishes
One-Pot Synthesis of 3,4-Dihydrocoumarins via C-H Oxidation/Conjugate Addition/Cyclization Cascade Reaction
作者:Dae Young Kim
DOI:10.3390/molecules28196853
日期:——
The 3,4-dihydrocoumarin derivatives were obtained from 2-alkyl phenols and oxazolones via C–H oxidation and cyclization cascade in the presence of silver oxide (Ag2O) and p-toluenesulfonic acid as a Brønsted acid catalyst. This approach provides a one-pot strategy to synthesize the multisubstituted 3,4-dihydrocoumarins with moderate to high yields (64–81%) and excellent diastereoselectivity (>20:1)
Organocatalytic Asymmetric [4 + 2] Cyclization of Azadienes with Azlactones: Access to Chiral 3-Amino-δ-Lactams Derivatives
作者:Wu-Jingyun Zhou、Xiaoning Yu、Chen Chen、Wei Lan、Gu Zhan、Jin Zhou、Qian Liu、Wei Huang、Qian-Qian Yang
DOI:10.1021/acs.joc.3c00663
日期:2023.10.6
a series of chiral δ-lactam frameworks have been synthesized and catalyzed by chiral phosphoric acid (CPA) utilizing two kinds of open-chain aza-dienes and azlactones derived from amino acids. This powerful [4 + 2] annulation produces a broad substrate scope with functional group tolerance in yield up to 97% with up to 98:2 er. Moreover, a facile scale-up and straightforward conversion to diversely