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Iodine catalyzed Mukaiyama–Michael reaction: experimental evaluation of catalytic effect in conjunction with computational study of the reaction mechanism
Author(s) -
Deuri Sanjib,
Phukan Prodeep
Publication year - 2012
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.2997
Subject(s) - chemistry , enol , reactivity (psychology) , catalysis , michael reaction , acrolein , silyl enol ether , computational chemistry , reaction mechanism , photochemistry , medicinal chemistry , methyl vinyl ketone , iodine , yield (engineering) , enol ether , organic chemistry , medicine , materials science , alternative medicine , pathology , metallurgy
The catalytic effect of iodine on Mukaiyama–Michael reaction has been evaluated experimentally taking three representative silyl enolates, which react effectively with various α,β‐unsaturated ketones in the presence of 10 mol% of iodine giving 1,5‐dicarbonyl products in 74%–87% yield. A study on the mechanism of the iodine catalyzed reaction has been carried out by density functional theory at the Becke, three‐parameter, Lee–Yang–Parr/6‐31G* level considering trihydrosilyl enol ether and acrolein as model system. Although the uncatalyzed reaction occurs through an asynchronous concerted bond formation process, two energetically competitive pathways (one concerted and the other stepwise) are possible for the catalyzed process. Iodine catalyzed MM reaction between methyl vinyl ketone and 1‐phenyl‐1‐(trimethylsilyloxy)‐ethylene involves a very low activation barrier compared with that of the simple trihydrosilyl enol ether/acrolein system. Catalytic effect of iodine was further confirmed by highest occupied molecular orbital–lowest unoccupied molecular orbital analysis and reactivity analysis using conceptual density functional theory based reactivity descriptors at Becke, three‐parameter, Lee–Yang–Parr/6‐31G** level. Copyright © 2012 John Wiley & Sons, Ltd.