Distannoxane speciation during esterification catalysis: revealing insights provided by electrospray ionization mass spectrometry

Abstract

Dimeric tetraalkyldistannoxanes are have been reported to catalyze esterification reactions, but are difficult to investigate in detail due to the lack of suitable spectroscopic handles. Electrospray ionization mass spectrometry (ESI-MS), in conjunction with a tethered charge on a tin atom, reveals that immediate decomposition to mono-tin carboxylate compounds occurs in the presence of carboxylic acid.

The application of electrospray ionization mass spectrometry to homogeneous catalysis

“…A key example of the usefulness of charged tags in probing reaction mechanisms is found in our study of the esterification of alcohols and carboxylic acids [93] reportedly catalyzed by distannoxanes [94]. A permanently-charged pyridinium group was incorporated into the proposed distannoxane catalyst and the catalyst was then readily observed by ESI(+)-MS in solutions of methanol and acetonitrile (Figure 16 a).…”

“…Their findings explain some general mechanistic findings in palladium cross coupling reactions. Our group's contributions to the area of developing and employing charged and chargeable ESI-MS tags include: the development of various chargeable or charged phosphine ligands analogous to commonly used mono-or bi-dentate neutral phosphine ligands [90][91][92]; using a tethered charged pyridinium group to study distannoxane speciation during esterification catalysis [93]; and examining olefin hydrogenation and silane dehydrocoupling with a charged analogue of Wilkinson's catalyst [91,92].…”

Organotin Compounds in Technology and Industry

“…Reactions at carboxyl groups, such as esterification, transesterification, transcarbamoylation, lactonisation, and ring-opening polymerisation (ROP) [equations (29)(30)(31)(32)(33)], are important in chemical industry. …”

Mechanistic elucidation of monoalkyltin(iv)-catalyzed esterification

“…[8][9][10][11] Although still under debate, the catalytic activity of these distannoxanes is often attributed to the unique cooperative behavior of the tin atoms in the distannoxanes. [12][13][14] For applications of distannoxanes as catalysts in transesterification reactions see the work of Otera and co-workers. [15][16][17] Monoalkyltin(IV) catalysts have received far less attention than the distannoxanes.…”