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Synthesis of 4‐Oxo‐but‐2‐enals through t BuONO and TEMPO‐Promoted Cascade Reactions of Homoallylic Alcohols
Author(s) -
He Yan,
Tian MiaoMiao,
Zhang XinYing,
Fan XueSen
Publication year - 2016
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.201600312
Subject(s) - chemistry , nitration , reagent , allylic rearrangement , hydrazine (antidepressant) , cascade , stereoselectivity , combinatorial chemistry , nitrite , nitro , alcohol , hydrate , medicinal chemistry , organic chemistry , catalysis , nitrate , chromatography , alkyl
An efficient and stereoselective synthesis of ( E )‐4‐oxo‐but‐2‐enals through tert ‐butyl nitrite ( t BuONO)‐ and 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO)‐promoted cascade reactions of homoallylic alcohols is presented. Mechanistically, the formation of the title compounds involves a cascade process including nitration of the carbon–carbon double bond, oxidation of the secondary alcohol unit, and Nef transformation of the in situ formed allylic nitro scaffold. In this process, t BuONO is an efficient nitration and oxidation reagent while TEMPO is believed to act as a mild oxidant and a novel reagent to promote the Nef reaction that is accomplished under mild and neutral conditions. As a further aspect, the ( E )‐4‐oxo‐but‐2‐enals thus obtained were found to be suitable substrates to condense with hydrazine hydrate to give diversely substituted pyridazines with good efficiency.