One potential Lewis acid that has received negligible attention as a catalyst is the carbocation. Here we show the potential of triaryl methylium ions as highly powerful Lewis acid catalysts for organic reactions. The Lewis acidity of the triaryl methylium ion can be easily tuned by variation of the electronic properties of the aromatic rings and the catalytic activity of the carbocation is sho...

We report herein the design, preparation and first applications of novel trityl tags with adjustable stability, efficient as protecting groups or MS analytes.

Motivated by the need for chemical strategies designed to tune peptide fragmentation to selective cleavage reactions, benzyl ring substituent influence on the relative formation of carbocation elimination (CCE) products from peptides with benzylamine-derivatized lysyl residues has been examined using collision-induced dissociation (CID) tandem mass spectrometry. Unsubstituted benzylamine-deriva...

On the other hand, the less stabilized tris(4chlorophenyl)methyl cation (1 b) was reported to initiate the polymerization of isobutene3). In accordance, p-methoxy and p-methyl substituted tritylium ions do not initiate the polymerization of a-methylstyrene, in contrast to the less stable 1 a and 1 b4). Only for few reactive monomers, however, the initiation was proven to proceed via addition of...

We have observed the branching rearrangement of a straight-chain secondary carbocation (C9H19+) in an ab initio molecular dynamics (AIMD) reverse-annealing (rising-temperature) simulation. The mechanism observed is one involving closed (protonated-cyclopropane) structures, previously observed in traditional geometry optimization calculations. However, the simulations give us a better understand...

The sesquiterpene synthase germacradiene-4-ol synthase (GdolS) from Streptomyces citricolor is one of only a few known high-fidelity terpene synthases that convert farnesyl diphosphate (FDP) into a single hydroxylated product. Crystals of unliganded GdolS-E248A diffracted to 1.50 Å and revealed a typical class 1 sesquiterpene synthase fold with the active site in an open conformation. The metal...