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Multimetallic Iridium‐Tin (Ir‐Sn 3 ) Catalyst in N ‐Acyliminium Ion Chemistry: Synthesis of 3‐Substituted Isoindolinones via Intra‐ and Intermolecular Amidoalkylation Reaction
Author(s) -
Maity Arnab Kumar,
Roy Sujit
Publication year - 2014
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201400234
Subject(s) - chemistry , iridium , nucleophile , catalysis , intramolecular force , tin , lewis acids and bases , medicinal chemistry , heteroatom , dimer , polymer chemistry , organic chemistry , ring (chemistry)
The multimetallic iridium‐tritin (Ir‐Sn 3 ) complex [Cp*Ir(SnCl 3 ) 2 {SnCl 2 (H 2 O) 2 }] ( 1 ) proved to be a highly effective catalyst towards COH bond activation of γ‐hydroxylactams, leading to a nucleophilic substitution reaction known as the α‐amidoalkylation reaction. Catalyst 1 can be easily synthesized from the reaction of (pentamethylcyclocyclopentadienyl)iridium dichloride dimer {[Cp*IrCl 2 ] 2 } and tin(II) dichloride (SnCl 2 ). In terms of catalyst loading, reaction conditions and yields of the product formed, 1 is found to be superior compared to classical Lewis acid catalysts. Different carbon (arenes, heteroarenes, allyltrimethylsilane, 1,3‐dicarbonyls) and heteroatom (alcohols, thiols, amides and sulfonamides) nucleophiles have been successfully employed in the intramolecular and intermolecular alkylations, as well as in heterocyclization reactions. In the majority of cases good to excellent yields of 3‐substituted isoindolinones and 5‐substituted pyrrolidin‐2‐ones have been obtained. Besides, the reactions are also atom economical and salt free. It is proposed that the multimetallic Ir‐Sn 3 catalyst behaves as a mild and selective Lewis acid to activate the γ ‐hydroxylactam towards the formation of the N ‐acyliminium ion; the latter being trapped by potent nucleophiles leading to the desired products.