- Regioselective Suzuki-Miyaura Reactions of the Bis(triflate) of 6,7-Dihydroxy-2,2-dimethylchroman-4-one
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6,7-Diarylchromanone derivatives were prepared by Suzuki-Miyaura reactions of the bis(triflate) of 6,7-dihydroxy-2,2-dimethylchroman-4-one. Due to electronic factors the first attack proceeded with very good site selectivity at position 7.
- Pajtás, Dávid,Dihen, Károly,Kónya, Krisztina,Langer, Peter
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- A Novel Synthesis of Precocenes. Efficient Synthesis and Regioselective O-Alkylation of Dihydroxy-2,2-dimethyl-4-chromanones
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The reactions of trihydroxybenzenes 1a-c and 3-methylbut-2-enoic acid (2) in a zinc chloride/water/phosphoryl chloride system afford either the new trihydroxyphenylbutenone derivatives 3b,c or dihydroxy-2,2-dimethyl-4-chromanones 4a-c in good yields.Compounds 3b,c can be cyclized in high yields to 4b,c in 5percent sodium hydroxide solution.Regioselective O-alkylation of 4a-c leads to 5a-f in good yields.O-Alkylation of 5a-f, followed by reduction and dehydration, results in the formation of precocene 3 (7d) and its regioisomer 7a-c,e,f.Methylation of 4a-c gives 6g-i.Subsequent reduction and dehydration affords precocene 2 (7h) and its regiosiomers 7g,i.
- Timar, Tibor,Jaszberenyi, J. Csaba
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p. 871 - 877
(2007/10/02)
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