A constellation of deuterium-labeled silanes as a simple mechanistic probe not requiring absolute configuration...

A new stereochemical probe for mechanisms at the silicon atom that is based on a deuterium-labeled silolane is synthesized and evaluated. The key synthetic step involves the hydrogenation of a 2,5-dihydrosilole with deuterium gas, giving a complex mixture of isochronic stereoisotopologues. The overall stereochemical imbalance of this mixture is evident in its (2) H NMR spectrum, which provides a good qualitative measure of changes in the configuration at the silicon atom. The technique is rapid, easy to use, and overcomes limitations and biases of traditional methods. The utility of this new procedure is demonstrated by tracking the stereochemical course of several classical reactions as well as contemporary catalytic transformations involving bond formation at the silicon atom.