Publications VU University Amsterdam in Angewandte Chemie
Angewandte Chemie 2014, 53, 9068 –9071
Nitrilium ions are reactive intermediates in a number of classic organic reactions, such as the Beckmann rearrangement, the Ritter, and the Ugi reaction. The isolation of the first stable nitrilium salts was reported by both Klages and Grill and Meerwein et al. in 1955, but the development and application of these imine synthons has remained rather limited. Lammertsma, Slootweg and co-workers have shown that readily accessible nitrilium triflates are very convenient building blocks for the synthesis of novel classes of phosphaamidines, phosphaamidinates, and bis(imino)phosphanes, thus allowing variation of all substituents. The full potential of these readily available P,N ligands in coordination chemistry and catalysis is currently being explored.
Angewandte Chemie 2014, DOI: 10.1002/anie.201405879
White phosphorus (P4) is the archetypal building block for organophosphorus compounds. Current conversions proceed through PCl3, which is obtained by halogenation of P4. The chlorine atoms are subsequently substituted with organic groups by salt metathesis, generating equimolar amounts of halogenide waste. Direct, selective processes are needed if chlorinated intermediates are to be circumvented. The synthetic chemistry group can now control P4 transformations by reacting P4 with congested aryl lithium reagents and B(C6F5)3, which gives unique, Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutane anions. Alkylating their nucleophilic site results in a non-symmetrical disubstituted bicyclic tetraphosphorus compounds. This method enables the formation of P-C bonds in a controlled fashion using white phosphorus as the starting material.