Isolation of reactive intermediates in deprotonation reactions with zinc alkyls

Abstract

Using single crystal X-ray diffraction analysis and quantum chemical calculations, a model system for metalation reactions, the deprotonation of (tert-butylamino)(piperidinomethyl)dimethyl-silane (1) with Et(2)Zn, was established allowing for the isolation of a reactive intermediate, the adduct structure [1·Et(2)Zn] (2).

Primary Amine Functionalization of Alkoxysilanes: Synthesis, Selectivity, and Mechanistic Insights

“…In order to broaden the synthetic scope of this type of reaction, we became interested in using primary lithium amides as opposed to the previously used secondary lithium amides (Scheme ). The resulting alkoxyaminosilanes C enable further functionalization on the silicon-bound NH unit because of its increased acidity as result of the α effect of silicon . Such types of compounds, and, in particular, their N-metalated derivatives, have already been used in coordination compounds. , However, because the synthesis of these mixed functionalized compounds via chlorosilanes is difficult and inefficient, the examples are scarce and limited to bulky substituents on nitrogen.…”

Intramolecular Trapping of Allenylzincs by Carbonyl Groups

“…In the case of 16b , subsequent intramolecular proton transfer from the NH group would prevent further cyclization and explain the formation of 18 and 19 after hydrolysis. The activation of intramolecular transfer upon chelation was recently discussed in the reaction of diethylzinc with silazanes The formation of a mixture of homopropargyl alcohol 20 and allenyl alcohol 21 in the presence of benzaldehyde proved that the expected allenylzinc was formed in the medium.…”

“…In the case of 16b , subsequent intramolecular proton transfer from the NH group would prevent further cyclization and explain the formation of 18 and 19 after hydrolysis. The activation of intramolecular transfer upon chelation was recently discussed in the reaction of diethylzinc with silazanes …”