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Pd‐Catalyzed Diastereoselective Intramolecular Amide α ‐C−H Arylation in Sterically Hindered Monospirooxindole Motifs
Author(s) -
Shukla Dipti,
Babu Srinivasarao Arulananda
Publication year - 2019
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.201801732
Subject(s) - stereocenter , intramolecular force , chemistry , steric effects , stereochemistry , amide , aryl , catalysis , medicinal chemistry , alkyl , organic chemistry , enantioselective synthesis
This paper reveals the diastereoselective Pd‐catalyzed intramolecular α‐C( sp 3 )−H arylation in amides. The intermolecular and intramolecular α‐arylation of tertiary C( sp 3 )−H bond of carbonyl compounds have been well documented in the literature. Nevertheless, the diastereoselective intramolecular α‐arylation of tertiary C( sp 3 )−H bond involving sterically hindered spirocyclic carbonyl substrates, especially amides remains a less explored task. Accordingly, we have demonstrated the diastereoselective Pd‐catalyzed intramolecular amide α‐arylation of tertiary C( sp 3 )−H bond using monospirooxindole‐based carboxamide substrates and construction of various sterically hindered 1,2‐bisspirooxindolopyrrolidines possessing contiguous vicinal quaternary stereocenters with high diastereoselectivity. Monospirooxindole‐based carboxamide substrates suitably positioned with an aryl halide unit and tertiary α‐C−H bond, which were required for investigating the intramolecular α‐C( sp 3 )−H arylation were assembled via the stereoselective [3+2] cycloaddition of azomethine ylides with acrylamides. The stereochemistry of monospirooxindoles and 1,2‐bisspirooxindolopyrrolidines possessing contiguous vicinal quaternary stereocenters was assigned based on the X‐ray structure analyses of representative compounds.