Molecular Iodine-Mediated α-Iodination of Carbonyl Compounds

Abstract

Malose Jack Mphahlele did his BSc at the University of Fort Hare. He obtained his MSc and PhD degrees in organic chemistry at the University of Pretoria and Rhodes University under the supervision of Professors Tomasz A. Modro and Perry T. Kaye, respectively. His research is directed towards the synthesis of biologically-relevant heteroatom-containing compounds. He is a professor of organic chemistry and current chairpersonThe electrophilic properties associated with iodine have been exploited in recent years to effect α-halogenation of carbonyl compounds and their α,β-unsaturated derivatives. In this review, molecular iodine is presented as a readilyavailable and easy-to-handle reagent to effect α-halogenation of carbonyl compounds in the presence or absence of catalysts.

Synthesis and cyclisation studies of (E)-2-aryl-1-methyl-3-styrylquinolin-4(1H)-ones

“…The cyclization into 2-arylquinolin-4(1H)-ones 2aec was not as easy as described in the literature. 3 It was necessary to study the reaction conditions, several combinations of solvents (THF and t-BuOH), y bases (NaH and t-BuOK), y temperature (from 30 C to 80 C and also MW irradiation) and different reactions times were tested in order to obtain the products in good yields. The best reaction conditions found for derivative 2a (t-BuOK as base and THF as solvent) were not appropriate for the other derivatives.…”

2,6,8‐Triaryl‐3‐iodoquinolin‐4(1H)‐ones as Substrates for the Synthesis of 2,3,6,8‐Tetraarylquinolin‐4(1H)‐ones and the 2‐Substituted 4,6,8‐Triaryl‐1H‐furo[3,2‐c]quinolines

“…Halogenation of quinolinone systems continues to attract considerable attention because of the profound effect; the introduction of a halogen atom into the heterocyclic ring can have on the physical, chemical, and biological properties of such systems. The electrophilic properties associated with iodine have been exploited in recent years to effect α‐halogenation of carbonyl compounds and their α,β‐unsaturated derivatives . Iodine and ceric ammonium nitrate (CAN: (NH 4 ) 2 Ce(NO 3 ) 6 ) in acetonitrile at 70–80°C afforded the 2‐aryl‐3‐iodoquinolin‐4(1 H )‐ones .…”

“…α,β‐Unsaturated carbonyl compounds readily undergo halogenation to afford α‐haloenones, which provide an important functional group that facilitates metal‐catalyzed CC bond formation . Displacement of halogen atom/s on the aryl or heteroaryl moiety of halogenated heterocycles by metal catalysts provides an avenue for the installation of a wide range of carbon‐containing (alkyl, alkenyl, alkynyl, and aryl) and even heteroatom‐containing substituents.…”

ChemInform Abstract: Synthesis of 2‐Arylquinolin‐4(1H)‐ones and Their Transformation to N‐Alkylated and O‐Alkylated Derivatives

“…The 3-halogenated NH-4-oxo derivatives 39 (R 0 ¼ Br, I) were treated with NaH in THF to afford the N-methylated derivatives 40 as the only products (Scheme 14) [41,50,51]. The observed regioselectivity was attributed to the preponderance of these derivatives as the NH-4oxo tautomers in polar medium and solid state [40,51].…”

“…This approach, which takes advantage of the ease of displacement of 4chlorine atom by nucleophiles has recently been used for the synthesis of 2,3-disubstituted 4-alkoxyquinoline derivatives (R 0 ¼ Me) that cannot be easily prepared otherwise. Series of 2-aryl-3-bromo/iodo-4-methoxyqui-nolines were prepared this way from the corresponding 2-aryl-4-chloro-3-halogenoquinolines [50,51,70]. This indirect approach has also been adapted to involve the use of organometalic reagents in the synthesis of 2,3-disubstituted 4-alkoxyquinolines.…”