An alkaloid-like 3-azabicyclo[3.3.1]non-3-ene library obtained from the bridged Ritter reaction

Chemo-selective control of Ritter-type reaction by coordinatively unsaturated inorganic salt hydrates

We used a readily available water source, MgSO4·2H2O, to realize the control of the chemo-selectivity of the Ritter-type reaction efficiently.

Synthesis of Aristoquinoline Enantiomers and Their Evaluation at the α3β4 Nicotinic Acetylcholine Receptor

The first synthesis of aristoquinoline (1), a naturally occurring nicotinic acetylcholine receptor (nAChR) antagonist, was accomplished using two different approaches. Comparison of the synthetic material's spectroscopic data to that of the isolated alkaloid identified a previously misassigned stereogenic center. An evaluation of each enantiomer's activity at the α3β4 nAChR revealed that (+)-1 is significantly more potent than (-)-1. This unexpected finding suggests that naturally occurring 1 possesses the opposite absolute configuration from indole-containing Aristotelia alkaloids.

The serendipitous effect of KF in Ritter reaction: Photo-induced amino-alkylation of alkenes

Ritter reaction has been recognized as an elegant strategy to construct the C−N bond. Its key feature is forming the carbocation for nucleophilic attack by nitriles. Herein, we report a complementary visible-light-induced three-component Ritter reaction of alkenes, nitriles, and α-bromo nitriles/esters, thereby providing mild and rapid access to various γ-amino nitriles/acids. Mechanistic studies indicated that traceless fluoride relay, transforming KF into imidoyl fluoride intermediate, is critical for the efficient reaction switch from atom transfer radical addition (ATRA) to the Ritter reaction. This approach to amino-alkylation of alkenes is chemoselective and operationally simple.

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Using light irradiation to promote amino-alkylation of alkenes

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Using KF to facilitate three-component Ritter reaction

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Access functionalized amides under mild conditions

Recent advances of Ritter reaction and its synthetic applications

This review provides a comprehensive survey of Ritter reactions from 2014 to 2020.

Antiproliferative activities of tricyclic amides derived from β-caryophyllene via the Ritter reaction against MDA-MB-231 breast cancer cells

A library of novel tricyclic amides has been synthesised via the Ritter reaction from β-caryophyllene 1 and its monoepoxy derivative 4. The compounds were assessed for antiproliferative activities against the aggressive MDA-MB-231 breast cancer cell line. Of the synthesised compounds, eight were active. 3c and 6b were the most potent and inhibited proliferation with IC₅₀ of 9.7 and 8.2 μM, respectively. Mechanistic studies revealed differences in their antiproliferative actions. 6b inhibited cell cycle progression and induced predominantly apoptotic cell death. In contrast, 3c did not affect cell cycle kinetics and favoured necrotic over apoptotic pathways. Screening against mammalian cells (VERO cells) indicates that 3c and 6b were more active towards MDA-MB-231 cells than noncancerous cells. Facile synthesis and biological results suggest that these caryophyllene derived amides are viable lead compounds for further development.

Regioselective and diastereoselective synthesis of two functionalized 1,5-methanoindeno[1,2-d]azocines via a three-component reaction

The morpholine promoted three-component reaction of N-alkylpiperidinone, indane-1,3-dione and 2-arylideneindane-1,3-dione in ethanol at room temperature resulted in the (1H-1,5-methanoindeno[1,2-d]azocin-12-ylidene)-1H-indene-1,3(2H)-dione derivatives in good yields and with exo-configuration.

Synthesis and Crystal Structure of Unexpected (1S,4R,5R,6S)-4-Cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonan-6-yl Acetate

The reaction of (–)-β-pinene with KCN under a mild bridged Ritter reaction gave (1S,5R,6S)-2,2,6-trimethyl-3-aza-bicyclo[3.3.1]non-3-en-6-yl acetate that subsequently reacted to provide an unexpected (1S,4R,5R,6S)-4-cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonane-6-yl acetate. The structure of the compound was determined by high-resolution mass spectrometry, and IR and NMR spectroscopy and confirmed by single crystal X-ray crystallography. The compound crystallises in the monoclinic P21 space group, with unit cell parameters a 8.6120 (17), b 7.4570 (15), c 11.189 (2) Å, and β 110.16 (3)°.