Synthesis and Characterization of Homoannularly Disubstituted and Heteroannularly Trisubstituted Ferrocene Derivatives by Arsenic and Silicon or by Arsenic and Tin

The ferrocene derivatives (5−10) homoannularly disubstituted and heteroannularly trisubstituted by
two different kinds of main-group elements, i.e., arsenic (As) and silicon (Si) or tin (Sn), were synthesized
from N,N-dimethylaminomethylferrocene (1) and its diphenylarsino derivative 2 through mono- or
dilithiation, followed by substitution with the organo-substituted chlorides RmMCln [R = alkyl, (m, n) =
(2, 2) or (3, 1)] of main-group elements M = As, Si, or Sn. The dimethylaminomethyl (−CH2NMe2)
group of the starting compounds facilitates lithiation of the cyclopentadienyl (Cp) ring and introduces
lithium into the ortho-position of the −CH2NMe2 groups by the directing functionality. The efficiency
of the subsequent substitution reaction with the organo-substituted chlorides RmMCln is influenced not
only by their reactivity but also by the spatial factors of the main-group elements and the ferrocene
derivative molecules to be reacted. All products 5−10 were identified by elemental analysis, proton
nuclear magnetic resonance (1H NMR) spectroscopy, and mass spectrometry (MS). Furthermore, the
X-ray crystal structure of 5 was determined. The application of 5, 6, and 10 to fungicides for crop plant
diseases was examined. The results of the percent inhibition test for fungal growth have indicated that
the derivative 10 has high fungicidal activity for early tomato blight.