The photoacetylation of diamondoids (nanodiamonds), in particular [1212]pentamantane, [1(2,3)4]pentamantane, and [123]tetramantane, with diacetyl almost exclusively gives apical acetyl derivatives. The mechanism of the photoacetylation was studied on the basis of a comparative analysis of the experimental deuterium kinetic isotope effects as well as the observed C–H bond substitution selectivities, which were also computed at the B3LYP, B3PW91, and MP2 levels of theory including polarized continuum modeling of solvent effects. The high apical C–H bond selectivities in the photoacetylation of diamondoids are determined by the higher polarizabilities of the cages along the apical direction in the transition structures for hydrogen abstraction with the triplet diacetyl diradical. Steric effects play only a minor role, and in combination with solvation, outweigh charge‐transfer effects that usually favor medial substitution with electrophiles and electrophilic radicals.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

We present an effective three-step chromatography-free sequence for the preparation of apical monohydroxy derivatives of diamantane, triamantane, and [121]tetramantane from the corresponding bis-apical diols utilizing tert-butyldimethylsilyl chloride as the monosilylating agent. The procedure was successfully applied to the monoprotection of several other aliphatic and aromatic diols. Additionally, 9-aminodiamantan-4-carboxylic acid, which has significant potential in medicinal and material sciences, was prepared through Ritter reaction of 4,9-dihydroxydiamantane in trifluoroacetic acid.

An effective three‐step sequence for the synthesis of monohydroxy diamantane, triamantane, and [12]tetramantane derivatives via monosilylation of diols is presented.

The cover picture shows shows the photochemical generation of triplet diacetyl (butadione, center) and its highly selective C–HH bond‐activation reactions in the functionalizations of tertiary C–H bonds. Despite several similarly reactive tertiary C–HH bonds and a multitude of secondary C–HH bonds with similar or even smaller bond dissociation energies (blue hydrogen atoms on structures on the left), this reagent shows remarkable selectivity for the apical positions of diamondoids owing to its high sensitivity to steric hindrance. This gives the respective apical acetyl diamondoids (blue groups on the right) in high yields. Deuterium kinetic isotope effects and accompanying computational studies shed light on the rate‐determining C–HH bond‐activation step. Details are discussed in the article by A. A. Fokin, P. R. Schreiner et al. on p. 5153 ff.