Dioxopyrrolines. XLVII. Thermal rearrangements of 7-vinyl derivatives of 1-aryl-5-ethoxycarbonyl-2-azabicyclo(3.2.0)heptane-3,4-diones and their imidates.
作者:Takehiro SANO、Yoshie HORIGUCHI、Suetaka KAMBE、Kazuhiko TANAKA、Jun'ichi TAGA、Jun TODA、Yoshisuke TSUDA
DOI:10.1248/cpb.38.1170
日期:——
Thermolysis of the 7-vinyl derivative of 1-aryl-5-ethoxycarbonyl-2-azabicyclo[3.2.0]heptane-3, 4-dione caused two different types of skeletal rearrangement depending on the stereochemistry of the 7-vinyl group. The exo-isomer (2) gave the hydroindole (4) by the 1, 3-shift of a C1-C7 bond to the vinyl group (path A reaction), while the endo-isomer (3) gave the 7-azabicyclo[4.2.1]nonane (5) by the Cope rearrangement (path B reaction). The product on thermolysis of the corresponding imidate also depends on the stereochemistry of the 7-vinyl group. The endo-isomer (13) gave the Cope product (12), while the exo-isomer (14) gave the dihydropyridone (16), which is produced by the 1, 3-shift of the C1-C7 bond to the C3 position followed by cheletropic loss of CO from the intermediary 2-azanorbornene (path C reaction). The validity of path C was proved by isolation of the 2-azanorbornenes (21 and 22) formed by thermolysis of the 7-vinyl-4-acetoxy imidate (20).
1-芳基-5-乙氧羧基-2-氮杂双环[3.2.0]庚烷-3,4-二酮的7-乙烯基衍生物的热分解导致了两种不同类型的骨架重排,具体取决于7-乙烯基基团的立体化学。外异构体(2)通过C1-C7键向乙烯基基团的1,3转移反应生成了氢吲哚(4)(路径A反应),而内异构体(3)则通过科普重排反应生成了7-氮杂双环[4.2.1]非烷(5)(路径B反应)。相应的氮杂亚胺的热分解产物也取决于7-乙烯基基团的立体化学。内异构体(13)生成了科普产物(12),而外异构体(14)则生成了二氢吡啶酮(16),其产生是通过C1-C7键向C3位置的1,3转移,并随后从中间体2-氮杂诺本二烯中脱去CO(路径C反应)。通过分离由7-乙烯基-4-乙酰氧基氮杂亚胺(20)热分解形成的2-氮杂诺本二烯(21和22),证明了路径C的有效性。