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Titanium(IV) Bromide and Boron(III) Tribromide Promoted Baylis‐Hillman Reactions of Arylaldehydes with But‐3‐yn‐2‐one
Author(s) -
Shi Min,
Wang ChunJiang
Publication year - 2002
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(200203)85:3<841::aid-hlca841>3.0.co;2-u
Subject(s) - chemistry , substituent , tribromide , allylic rearrangement , bromide , medicinal chemistry , titanium , boron , substrate (aquarium) , coupling reaction , organic chemistry , halogenation , catalysis , oceanography , geology
The reaction of arylaldehydes with but‐3‐yn‐2‐one in the presence of the Lewis acids titanium(IV) bromide (TiBr 4 ) or boron(III) tribromide (BBr 3 ) (1.4 equiv.) can be drastically affected by the reaction temperature. When the reaction was carried out at ≤−20°, the brominated compound 1 was obtained as the major product. However, when the reaction was carried out at room temperature (20°), both the brominated compound 1 and dibrominated compound 2 were formed as major products. The substituent on the phenyl ring can affect the ( E )/( Z ) ratio. Moreover, with 2 as the substrate, the Pd‐catalyzed allylic substitution and Suzuki ‐type coupling reaction have been examined.