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Palladium(0)‐Catalyzed Synthesis of 2‐Vinyl‐2,3‐dihydro‐benzo[1,4]dioxins
Author(s) -
Massacret Magali,
Lhoste Paul,
Lakhmiri Rajae,
Parella Teodor,
Sinou Denis
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199910)1999:10<2665::aid-ejoc2665>3.0.co;2-0
Subject(s) - chemistry , palladium , allylic rearrangement , medicinal chemistry , nitrobenzene , benzene , catalysis , nitro , steric effects , diol , alkyl , stereochemistry , organic chemistry
The reaction of 1,4‐bis(methoxycarbonyloxy)but‐2‐ene ( 2a–3a ) or 3,4‐bis(methoxycarbonyloxy)but‐1‐ene ( 4a ) with various substituted benzene‐1,2‐diols was catalyzed by a palladium(0) complex to give substituted 2‐vinyl‐2,3‐dihydro‐benzo[1,4]dioxins in good yields via a tandem allylic substitution reaction. In the case of 4‐substituted benzene‐1,2‐diols, the ratio of regioisomers is determined by the relative acidity of the two phenolic protons. For 3‐substituted benzene‐1,2‐diols, this ratio is determined only by steric effects in the case of alkyl substituents, although it is determined mainly by the relative stabilities of the corresponding phenates for other substituents; however, for 3‐nitrobenzene‐1,2‐diol, this ratio is determined by the relative leaving‐group ability of 2‐nitro‐ or 3‐nitrophenate. When the cyclisation was performed in the presence of an optically active phosphane, chiral 2‐vinyl‐2,3‐dihydro‐benzo[1,4]dioxin ( 5 ) was obtained with enantioselectivity of up to 45% using BINAP as the chiral phosphane.