Palladium(0)-Catalyzed Synthesis of 2-Vinyl-2,3-dihydro-benzo[1,4]dioxins

✍ Scribed by Magali Massacret; Paul Lhoste; Rajae Lakhmiri; Teodor Parella; Denis Sinou

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 395 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199910)1999:10<2665::aid-ejoc2665>3.0.co;2-0

✦ Synopsis

The reaction of 1,4-bis(methoxycarbonyloxy)but-2-ene (2a-effects in the case of alkyl substituents, although it is determined mainly by the relative stabilities of the 3a) or 3,4-bis(methoxycarbonyloxy)but-1-ene (4a) with various substituted benzene-1,2-diols was catalyzed by a corresponding phenates for other substituents; however, for 3-nitrobenzene-1,2-diol, this ratio is determined by the palladium(0) complex to give substituted 2-vinyl-2,3dihydro-benzo [1,4]dioxins in good yields via a tandem allylic relative leaving-group ability of 2-nitro-or 3-nitrophenate.

When the cyclisation was performed in the presence of an substitution reaction. In the case of 4-substituted benzene-1,2-diols, the ratio of regioisomers is determined by the optically active phosphane, chiral 2-vinyl-2,3-dihydrobenzo[1,4]dioxin (5) was obtained with enantio-selectivity of relative acidity of the two phenolic protons. For 3-substituted benzene-1,2-diols, this ratio is determined only by steric up to 45% using BINAP as the chiral phosphane.