摘要:
Protection of formylferrocene with propanediol under acidic conditions furnishes its acetal. Metalation of the acetal occurs mainly in the ortho position at the same ring. Reaction with N-formylpiperidine leads to the semiprotected 1,2-diformylferrocene, and the monoacetal of 1,1',2-triformylferrocene, which can be obtained upon acidic deacetalization. Further protection of the semiprotected 1,2-diformylferrocene with propanediol results in the corresponding bisacetal, which is metalated to give the title compound 1,2,3-triformylferrocene after quenching of the anion with N-formylpiperidine and acidic deprotection. The 1,1',2-triformylferrocene undergoes an interesting solid-state reaction at 170 degreesC under cross-linking to yield a novel organometallic polycondensate, while 1,2,3-triformylferrocene melts undecomposed. 1,2-Diformylferrocene was transformed into 1,2-bisbutadiynylferrocene by treatment with Taber's reagent, followed by coupling of 1,2-diethynylferrocene to bromo-triisopropylsilylethyne under Cadiot-Chodkiewicz conditions in an overall 40% yield starting from diformylferrocene. (C) 2001 Elsevier Science B.V. All rights reserved.