从1,1-二茂铁-1- methoxypropyne开始,第一空气稳定Ç 5 -cumulenium盐(FC)2 C ^ C ^ C ^ C ^ C(Fc)的+ BF 4 -(FC =二茂铁基)可通过金属化来合成,碘化,交叉偶联和脱水过程。尝试对二茂铁基碳负离子的亲核攻击仅提供自由基分解产物,而没有提供所需的四茂铁基-C 5-异丙苯(Fc)2 C C C C C C(Fc)2。相反,与苯基锂反应生成亲核加成产物(Fc)2 C C C(R)C⋮CFc(R = C6 H 5)具有100%的区域选择性。从二铁茂铁基酮开始,通过用二铁茂铁基(甲氧基)甲基逐步取代丙炔来制备第一种空气稳定的质子化的C 5 -ule鎓盐(Fc)2 CCH C C C(Fc)2 + BF 4- 。褶皱脱水。加入甲醇盐得到(Fc)2 C C C(R)CH 3 C(Fc)2(R = OCH 3); n =1。试图转化为四茂铁基-C
从1,1-二茂铁-1- methoxypropyne开始,第一空气稳定Ç 5 -cumulenium盐(FC)2 C ^ C ^ C ^ C ^ C(Fc)的+ BF 4 -(FC =二茂铁基)可通过金属化来合成,碘化,交叉偶联和脱水过程。尝试对二茂铁基碳负离子的亲核攻击仅提供自由基分解产物,而没有提供所需的四茂铁基-C 5-异丙苯(Fc)2 C C C C C C(Fc)2。相反,与苯基锂反应生成亲核加成产物(Fc)2 C C C(R)C⋮CFc(R = C6 H 5)具有100%的区域选择性。从二铁茂铁基酮开始,通过用二铁茂铁基(甲氧基)甲基逐步取代丙炔来制备第一种空气稳定的质子化的C 5 -ule鎓盐(Fc)2 CCH C C C(Fc)2 + BF 4- 。褶皱脱水。加入甲醇盐得到(Fc)2 C C C(R)CH 3 C(Fc)2(R = OCH 3); n =1。试图转化为四茂铁基-C
Copper-mediated cross-coupling of diferrocenyl propargylic and homopropargylic C-3 and C-4 building blocks yields an alpha,omega -dimethoxy-tetraferrocenyl C-7 cumulene precursor together with a C-8 home-coupled byproduct. Subsequent acid-promoted twofold elimination of methanol gives access to tetraferrocenylheptapentaenylium tetrafluoroborate which can be deprotonated by non-nucleophilic strong bases to cumulene (Fc)(2)C-7(Fc)(2). Although this compound can be handled in solution only, UV-vis spectroscopic evidence and trapping experiments (hydrolysis and transition metal complex formation) support the existence of this first compound containing seven cumulated carbons. (C) 2001 Elsevier Science B.V. All rights reserved.