Furopyridines. XX. Wittig-horner reaction of a phosphonate of reissert analogues of furo[3,2-<i>c</i>]-, -[2,3-<i>c</i>]- and -[3,2-<i>b</i>]pyridines
作者:Shunsaku Shiotani、Youichi Tsukamoto、Yasuyuki Kitagawa
DOI:10.1002/jhet.5570340121
日期:1997.1
Furo[3,2-c]-(1a), -[2,3-c]- (1b) and -[3,2-b]pyridine (1c) were reacted with isopropyl chloroformate and trimethyl phosphite to give dimethyl 5-isopropoxycarbonyl-4,5-dihydrofuro[3,2-c]pyridine-4-phosphonate (2a), dimethyl 6-isopropoxycarbonyl-6,7-dihydrofuro[2,3-c]pyridine-7-phosphonate (2b) and dimethyl 4-isopropoxycarbonyl-4,7-dihydrofuro[3,2-b]pyridine-7-phosphonate (2c) as unstable syrups. Reaction
将呋喃并[3,2- c ]-(1a),-[2,3- c ]-(1b)和-[3,2- b ]吡啶(1c)与氯甲酸异丙酯和亚磷酸三甲酯反应生成二甲基5 -异丙氧基羰基-4,5-二氢呋喃[3,2-c]吡啶-4-膦酸酯(2a),6-异丙氧基羰基-6,7-二氢呋喃二甲基[2,3 - c ]吡啶-7-膦酸酯二甲酯(2b)和作为不稳定糖浆的4-异丙氧基氧羰基-4,7-二氢呋喃[3,2- b ]吡啶-7-膦酸二甲酯(2c)。的反应图2b和2c中以Ñ丁基锂,然后用苯甲醛,p-甲氧基苯甲醛,对-氰基苯甲醛或丙醛可提供正常的Wittig反应产物5b-H,5b-OMe,5b-CN,5b-Et,5c-H,5c-H,5c-OMe和5c-CN,除了2b用丙醛。同时,化合物2a的相同反应和2b与丙醛的反应提供了出乎意料的产物,5-异丙氧基羰基呋喃[3,2 - c ]吡啶基-4-芳基-(或乙基)甲醇3a-H,3a-OMe