Ligand-stabilized copper(I)-hydride catalyzes the dehydrogenative Si-O coupling of alcohols and silanes-a process that was found to proceed without racemization at the silicon atom if asymmetrically substituted. The present investigation starts from this pivotal observation since silicon-stereogenic silanes are thereby suitable for the reagent-controlled kinetic resolution of racemic alcohols, in which asymmetry at the silicon atom enables discrimination of enantiomeric alcohols. In this full account, we summarize our efforts to systematically examine this unusual strategy of diastereoselective alcohol silylation. Ligand (sufficient reactivity with moderately electron-rich monophosphines), silane (reasonable diastereocontrol with cyclic silanes having a distinct substitution pattern) as well as substrate identification (chelating donor as a requirement) are introductorily described. With these basic data at hand, the substrate scope was defined employing enantiomerically enriched tert-butyl-substituted 1-silatetraline and highly reactive 1-silaindane. The synthetic part is complemented by the determination of the stereochemical course at the silicon atom in the Si-O coupling step followed by its quantum-chemical analysis thus providing a solid mechanistic picture of this remarkable transformation.

A cascade of five steps, transforms cyclooctynes in the presence of nucleophiles NuH and nitrous oxide, into the depicted products (see scheme). In another example, nitrous oxide was added at a cycloalkyne at −25 °C to generate the corresponding diazo ketone. In both cases, all three atoms of nitrous oxide were incorporated into the products.

Durch eine Kaskade von fünf Schritten wurden Cyclooctine in Gegenwart der Nucleophile NuH und mithilfe von N2O in die gezeigten Produkte umgewandelt. In einem weiteren Beispiel wurde N2O bei −25 °C an ein Cycloalkin addiert, um das entsprechende Diazoketon zu erzeugen. In beiden Fällen wurden alle drei N2O‐Atome in die Produkte eingebaut.

Cyclooctyne and cycloocten-5-yne undergo, at room temperature, a 1,3-dipolar cycloaddition with dialkyl acetylenedicarboxylates 1a,b to generate furan-derived short-lived intermediates 2, which can be trapped by two additional equivalents of 1a,b or alternatively by methanol, phenol, water or aldehydes to yield polycyclic products 3b-d, orthoesters 4a-c, ketones 5 or epoxides 6a,b, respectively. Treatment of bis(trimethylsilyl) acetylenedicarboxylate (1c) with cyclooctyne leads to the ketone 7 via retro-Brook rearrangement of the dipolar intermediate 2c. In all cases, the products are formed with perfect atom economy.