IKARIYA Takao NKK, Technical Research Center, Manager, 中央研究所第四研究部, 主査
ISHII Youichi The University of Tokyo, Fac. of Eng., Research Associate, 工学部, 助手 (40193263)
|Budget Amount *help
¥6,600,000 (Direct Cost : ¥6,600,000)
Fiscal Year 1990 : ¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1989 : ¥4,600,000 (Direct Cost : ¥4,600,000)
|Keywords||Cyclocarbonylation / Palladium Catalyst / 2, 6-Naphthalenedicarboxylic Acid / Fused Heteroaromatic Compounds / 3, 3-Diarylallyl Acetates / Phenyl Acetates / 2, 4-Pentadienyl Acetates / 酢酸3,3ージアリ-ルアリル / 酢酸2,4ーペンタジエニル / 1ーアセトキシー3,7ージメチルナフタレン / 5ーヒドロキシー1ーナフトエ酸 / 液晶 / ジフェニルケテン|
With the aim of developing of a novel route to 2, 6-naphthalenedicarboxlic acid 1, the palladium catalyzed cyclocarbonylation was extensively studied. The major results are as follows :
1. Cyclocarbonylation of 2-methyl-3-(p-tolyl)allyl acetate in the presence of NEt_3, Ac_2O, and a catalytic amount of PdCl_2(PPh_3)_2 gave 1-acetoxy-3, 7-dimethylnaphthalene in a good yield, which was converted to the corresponding benzenesulfonate. Hydrogenolysis of the benzenesulfonate catalyzed by Pd(OAc)_2-dppb afforded 2,6-dimethylnaphthalene, whose oxidation to 1 is well-known. Therefore these reactions accomplish a novel route to 1. Synthesis of 5-acetoxy-1-naphthoic acid via the cyclocarbonytlation and physical properties of its copolymer with 4-acetoxybenzoic acid were also investigated.
2. Acetoxybenzofurans, acetoxybenzothiophenes, acetoxyindoles, and acetoxycarbazoles were obtained in high yields by the cyclocarbonylation of 3-furyl, 3-thienyl, 3-pyrrolyl, and 3-indolylallyl acetates, respectively. The synthetic utility of the reaction was demonstrated by the synthesis of cannabifuran from isothymol.
3. Cyclocarbonylation of 3,3-diarylallyl acetates afforded p-aryl-substituted fused phenyl acetates where the cyclization occurred selectively on the more electron rich ring. This result suggests that the reaction involves the intramolecular electrophilic attack of the acyl group coordinated by palladium on the aromatic ring.
4. Cyclocarbonylation of 2, 4-pentadienyl acetates was revealed to give phenyl acetates in good yields. This reaction provides a versatile and general synthetic route to substituted phenyl esters including 3, 5- or 2, 3- disubstituted ones, which are hardly obtainable by conventional electrophilic subs titution reactions of phenol.