Palladium(0)-Catalyzed Coupling Reactions of 2-Alkoxy-1-ethynylcyclopropanes with Aryl and Ethenyl Halides: Preparation of Cyclopropyl Substituted Ethynylarenes, Eneynes and Enediynes
作者:Gregory Mcgaffin、Armin de Meijere
DOI:10.1055/s-1994-25528
日期:——
2-Alkoxy-1-ethynylcyclopropanes 1-R 1, readily available in diastereo- and enantiopure form, 2,3 undergo facile palladium-catalyzed cross-coupling reactions with various mono- and oligohaloarenes 2(a-c)-X, 4, 6, 9, 12, haloalkenes 14a-d and (E/Z)-1,2-dihaloethenes [(E/Z)-18-X]. The trans- and trans/cis-(2-alkoxycyclopropyl)-ethynyl derivatives 3(a-c)-R 1, 5, 7, 10, 13, 15a-d and (E)-19(22) were exclusively obtained in good to excellent yields. The coupling reaction thus opens the first direct access to configurationally uniform (2-alkoxycyclopropyl)ethynyl substituted arenes, and 2-alkoxycyclopropyl substituted eneynes and enediynes. Catalytic hydrogenation of ethynylarenes 3(a-c)-R 1, 10, and 13 smoothly afforded the corresponding (E/Z)-[(2-alkoxycyclopropyl) ethenyl]arenes 24(a-c)-R 1, 25 and 26, which are not directly accessible by palladium(0)-catalyzed coupling reactions of (E)-2-alkoxy-1-ethenylcyclopropanes with haloarenes.
2-烷氧基-1-乙炔基环丙烷 1-R 1,容易获得的二氟和对映体纯形态 2,3,经过简单的钯催化交叉偶联反应,与各种单卤和寡卤芳烃 2(a-c)-X, 4, 6, 9, 12,卤代烯烃 14a-d 和 (E/Z)-1,2-二卤乙烯 [(E/Z)-18-X] 反应。转型和转/顺-(2-烷氧基环丙基)-乙炔衍生物 3(a-c)-R 1, 5, 7, 10, 13, 15a-d 和 (E)-19(22) 在良好到优异的收率下独家获得。该偶联反应首次打开了构象均匀的 (2-烷氧基环丙基)乙炔取代芳烃,以及 2-烷氧基环丙基取代烯炔和烯二炔的直接通道。乙炔芳烃 3(a-c)-R 1, 10 和 13 的催化氢化顺利提供了相应的 (E/Z)-[(2-烷氧基环丙基)乙烯基]芳烃 24(a-c)-R 1, 25 和 26,这些化合物不能通过 (E)-2-烷氧基-1-乙烯基环丙烷与卤代芳烃的钯(0)催化偶联反应直接获得。