Transition metal-mediated condensation reactions

Transition-metal mediated condensation of esters and aldehydes is known. The reaction of a thioester and an aryl aldehyde with TiCLi—NBU3, for example, gave a p-hydroxy thioester with good syn selectivity. Selenoamides [RCH2C(=Se)NRy react with EDA and then an aldehyde to give p-hydroxy selenoamides. ... 

Pyrrolo[3,2-df pyridazines are a class of interesting and useful A -heterocycles [40—42]. However, synthetic methods for such heterocyclic compounds have been very much limited such as condensation of pyrrole-2,3-diones with hydrazine. There are no reports on one-pot multi-component synthesis of pyrrolo[3,2-(f py-ridazines [43]. Moreover, synthetic methods for pyrrole-2,3-diones are also very limited [43]. On the other hand, transition-metal-mediated reactions of azides are of great importance and versatility in organic synthesis, because azides could be readily transformed into a wide variety of valuable A -containing natural products and medicinal agents [44-50]. 

Applications of electrospray mass spectrometry (ESMS) to the study of reactions mediated by transition-metal complexes are reviewed. ESMS has become increasingly popular as an analytical tool in inorganic and organometallic chemistry, in particular with regard to the identification of short-lived intermediates of catalytic cycles. Going one step further, the coupling of electrospray ionization to ion-molecule techniques in the gas phase yields detailed information about single reaction steps of catalytic cycles. This method allows the study of transient intermediates that have previously not been within reach of condensed-phase techniques on both a qualitative and quantitative level. 

---