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Phosphotungstic Acid as an Efficient Catalyst for Allylation of Isatins and N ‐ tert ‐Butyloxycarbonylamido Sulfones Under Solvent‐Free Conditions
Author(s) -
Ghosh Debashis,
Saravanan S.,
Gupta Naveen,
Abdi Sayed H. R.,
Khan Noorul H.,
Kureshy Rukhsana I.,
Bajaj Hari C.
Publication year - 2014
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201402130
Subject(s) - isatin , chemistry , phosphotungstic acid , catalysis , organic chemistry , solvent , medicinal chemistry , combinatorial chemistry
The present work demonstrates the use of phosphotungstic acid (H 3 PW 12 O 40 ⋅ H 2 O) as an efficient catalyst for the allylation of isatin derivatives as well as N ‐ tert ‐butyloxycarbonyl (Boc)‐α‐amido sulfones with allyltributyltin as an allylating agent under solvent‐free conditions at room temperature. Excellent allylation product yields of up to 99 % for the isatins substrates and good to excellent yields of up to 98 % for the N ‐Boc α‐amido sulfones were obtained. The present allylation protocol is scalable as demonstrated by allylation of N ‐methylisatin at 1 g scale. Based on 1 H, 13 C, and 31 P NMR studies a catalytic cycle was proposed for allylation of isatins as well as N ‐Boc amido sulfones. The allylation products N ‐Boc homoallyl amines were successfully epoxidized to get multifunctional compounds, which are valuable intermediates for natural products and bioactive compounds.