Green Organocatalytic Synthesis of Indolines and Pyrrolidines from Alkenes

Abstract

Employing a green and efficient 2,2,2‐trifluoroacetophenone‐catalyzed oxidation of alkenes, which utilizes H2O2 as the green oxidant, a novel and sustainable synthesis of indolines and pyrrolidines was developed. This constitutes a cheap, general and environmentally‐friendly protocol for the synthesis of substituted nitrogen‐containing heterocycles. A variety of substitution patterns, both aromatic and aliphatic moieties, are well tolerated leading to the desired nitrogen heterocycles in good to excellent yields.magnified image

Green Organocatalytic Oxidative Methods using Activated Ketones

“…Utilizing o ‐allylanilines and phenols as starting materials, a variety of indolines, pyrrolidines, and dihydrobenzofurans can be synthesized. In the first step, the olefinic group is epoxidized, and subsequently, the functional group attacks the ring and opens the epoxide to afford the desired cyclized product, with or without the use of a suitable additive (Schemes and ).…”

“…Benzofuransa nd indolines are bicyclic compounds that possess av ery important skeleton for pharmaceuticals, bioactive compounds, and natural products. [102,103] Utilizing o-allylanilines andp henols as starting materials, a variety of indolines, [104] pyrrolidines, [104] and dihydrobenzofurans [105] can be synthesized. In the first step, the olefinic group is epoxidized, and subsequently,t he functional group attacks the ring and opens the epoxide to afford the desired cyclized product, with or without the use of as uitable additive (Schemes 28 and 29).…”

Synthesis of Benzofuran and Indole Derivatives Catalyzed by Palladium on Carbon

“…We have been interested in developing new, green and sustainable processes for the synthesis of compounds . Along these lines, we had previously introduced organocatalytic oxidation protocols for the synthesis of benzodihydrofurans and indolidines , . Herein, our goal was to introduce a sustainable methodology for the synthesis of the family of indoles and benzofurans.…”

Crystal packing analysis of in situ cryocrystallized 2,2,2-trifluoroacetophenone

“…Research work in recent years has shown that TFAP can be used as a green organocatalyst in synthetic procedures, e.g. for the epoxidation of alkenes (Limnios & Kokotos, 2014a), the oxidation of allyloximes to form isoxazoline (Triandafillidi & Kokotos, 2017), the oxidation of aliphatic tertiary amines and azines (Limnios & Kokotos, 2014b) and for the synthesis of substituted tetra-hydrofurans (Theodorou & Kokotos, 2017a), indolines and pyrrolidines (Theodorou & Kokotos, 2017b), besides being used for the synthesis of fluorinated polymers (Guzmá n-Gutié rrez et al, 2008). Interestingly, TFAP has been also used for probing intermolecular interactions involved in the bi-molecular complexes formed on Pt(111) surfaces (Goubert et al, 2011).…”