reaction conditions. The reaction could be carried out on a gram scale with the good results being maintained. Control experiments were performed to elucidate the specific diastereoselectivity of the reaction. The formation of single trans isomers was dominated by secondary orbital interactions between the ester groups of the dipolarophile and the azomethineimine. On the basis of the experimental results
efficient catalytic asymmetric Friedel–Crafts alkylation of indoles with alkylidene malonates has been developed by using a chiral N,N′‐dioxide–Sc(OTf)3 complex as the catalyst (see scheme). Some opticallyactive intermediates containing the indole skeleton have been synthesized, such as indolepropionic acid, tryptamines, and β‐carbolines. The coordination between the scandium atom and the chiral N,N′‐dioxide
The asymmetric direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactams with alkylidene malonates has been developed. Various 5-substituted 3-pyrrolidin-2-ones were obtained in high yields (up to 93%) with excellent stereoselectivities (up to 94% ee, 95â:â5 dr), using a novel bifunctional C1-symmetric guanidine organocatalyst embodied a secondary amine subunit.
Construction of Octahydro‐4<i>H</i>‐cyclopenta[<i>b</i>]pyridin‐6‐one Skeletons using Pot, Atom, and Step Economy (PASE) Synthesis
作者:Silver Raju、Palash Ghosh、Kiranmai Nayani、Jupally Prashanth、Balasubramanian Sridhar、Prathama S. Mainkar、Srivari Chandrasekhar
DOI:10.1002/chem.202301058
日期:2023.8.21
A Lewisacidcatalyzed cascade aza-Piancatelli reaction and [3+3]/[4+2] cycloadditionreaction to access octahydro-4H-cyclopenta[b]pyridin-6-one, octahydro-5,7a-epoxycyclopenta[cd]isoindol-4-one and decahydro-1H-dicyclopenta[cd,hi]isoindol-6-one skeletons.
Lewis酸催化级联氮杂-Piancatelli反应和[3+3]/[4+2]环加成反应得到八氢-4H-环戊基[ b ]吡啶-6-酮、八氢-5,7a-环氧环戊基[ cd ]异吲哚-4-酮和十氢-1 H-二环五[ cd , hi ]异吲哚-6-酮骨架。
N,N′-Dioxide–scandium(III) complex catalyzed highly enantioselective Friedel–Crafts alkylation of indole to alkylidene malonates
A highly efficient enantioselective Friedel-Crafts alkylation of indoles with alkylidene malonates has been developed using chiral N,N'-dioxide LA-scandium(III) complex as the catalyst, giving the corresponding products in high yields with excellent enantioselectivities (up to 99% yield and 95% ee). The product 3a was facilely converted into several interesting compounds, such as tryptamines, indolepropionic acids and beta-carbolines. It is noteworthy that the seven-membered beta-carboline-like compound has been synthesized for the first time. Based on the crystal structure of the chiral N,N'-dioxide L10-scandium(III) complex, the proposed transition state and possible catalytic cycle were presented to elucidate the reaction mechanism. (C) 2009 Elsevier Ltd. All rights reserved.