Cyclotrimerization Reactions with Manganese and Cobalt: Catalytic twins?
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
21st International Symposium on Organometallic Chemistry Directed Toward Organic Synthesis
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
Transition metal-catalyzed cycloaddition reactions have become particularly successful examples for
high versatile and atom-efficient transformations with [2+2+2] cycloaddition reactions as a particular
versatile representative. This reaction stands out as a large number of transition metals are capable
to mediate or catalyze this reaction.1 The late metals of the first row of the transition metals have
been among the first, from which successful examples of catalytic cyclotrimerizations have been
reported.2 These metals, especially nickel and cobalt, exhibit interesting and unique catalytic features
compared to the heavier congeners. Most recently our studies led to the discovery of a Co(II)-based
catalytic process for the synthesis of phosphinines from diynes and phosphaalkynes, featuring a large
substrate scope including even tolerance to nitrile groups in the substrates.3 While our interest is
focusing on developing new catalysts and exploiting different oxidation states, we are also interested
in discovering the catalytic features of other 3d metals like iron and especially manganese. Except for
a few (formal) examples, manganese complexes were not known to catalyze cyclotrimerization
reactions so far, although the Cp (cyclopentadienyl) and CO complexes share structural similarities to
those of cobalt. The presentation will discuss the development of novel manganese catalysts for
[2+2+2] cycloadditions, their catalytic features and scope of substrates, including a comparison to
cobalt-catalyzed transformations and reaction mechanisms, and their evolution to master new
substrate challenges.