| Summary: | 碩士 === 靜宜大學 === 應用化學研究所 === 95 === Reaction of cyclic enol ethers such as 2,3-dihydrofuran and 3,4-dihydro-2H-pyran with a variety of β-dicabonyls 2.1 such as 2,4-pentanedione 2.1a, ethyl acetoacetate 2.1b, 1-phenyl-1,3-butanedione 2.1c, 1,3-diphenyl-1,3-propanedione 2.1d, 1,3-cyclohexanedione 2.1e, 5,5-dimethyl-1,3-cyclohexanedione 2.1f, and 4-hydroxycoumarin 2.1g , catalyzed by using 10 mol% of iodotrimethylsilane (TMSI), afforded a series of the corresponding O-tetrahydrofuranyl (O-THF) ethers 2.2 and O-tetrahydropyranyl (O-THP) ethers 2.3 in high yields, respectively. Similarly, this methodology was applied to the reaction of 3,4,6-tri-O-acetyl- D-glucal (TAG) with cyclic β-dicabonyls 2.1 such as 1,3-cyclohexanedione 2.1e and 5,5-dimethyl-1,3-cyclohexanedione 2.1f afforded the corresponding α-2-deoxy-C-glycosides 2.4. Reaction of TAG with a variety of acyclic β-dicabonyls 2.1 such as 2,4-pentanedione 2.1a, ethyl acetoacetate 2.1b, 1-phenyl-1,3-butanedione 2.1c and 1,3-diphenyl-1,3-propanedione 2.1d, afforded the corresponding of α-2,3-unsaturated-C-glycosides 2.5.
Reaction of TAG with a variety of phenol derivatives 2.6 such as anisole 2.6c, 3-methoxyphenol 2.6d, 4-methoxyphenol 2.6e, 4-cyanophenol 2.6f, 4-chlorophenol 2.6g, 3-chlorophenol 2.6h, 4-bromophenol 2.6i, 3-bromophenol 2.6j and 4-nitrophenol 2.6k, catalyzed by using 10 mol% of TMSI afforded a series of aryl α-2,3-unsaturated-O-glycosides 2.7; however, reaction of TAG with phenol 2.6a and 2-methylphenol 2.6b afforded aryl α-2-deoxy-O-glycosides 2.8.
Reaction of TAG with phenols possessing a moderate electron withdrawing group such as 2.6f, 2.6g, 2.6h, 2.6i and 2.j, mediated by using one equivalent of TMSI afforded the corresponding of aryl α-2,3-dideoxy-3-iodo glycosides 2.9; however, reaction with the rest of phenols 2.6 gave the corresponding of aryl α-2,3-unsaturated-O-glycosides 2.7.
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