Stereochemically Pure Si‐Chiral Aminochlorosilanes

Abstract

Silicon‐based compounds with stereochemical information and convertible functional units are valuable building blocks in synthetic chemistry. Si‐stereogenic aminochlorosilanes are built up by Si−N bond formation between an achiral dichlorosilane and a chiral enantiomerically pure primary amine. Both diastereomers could be isolated as stereochemically pure single‐crystals by fractional crystallization and were analyzed by X‐ray crystallography. Defined intermolecular interaction patterns were identified illustrating the role of N−H⋅⋅⋅π, C−H⋅⋅⋅π, and N−H⋅⋅⋅Cl contacts in the molecular crystalline packing arrangements. Stepwise functionalization of the silicon−chlorine and silicon−amine functions was carried out, demonstrating their potential for use as a chiral synthesis precursors. Via optically pure aminomethoxysilanes, enantiomerically enriched methoxysilanols, chloromethoxysilanes, and methoxysilanethiols were synthesized. The stereospecificity of the transformations was monitored. The (R)‐BINOL‐PSSLi method for determining the enantiomeric purity was found to be the tool of choice for acid‐sensitive silanols and silanethiols.