The success of the olefin metathesis reaction, a key reaction in organic chemistry,
polymer chemistry and catalyst development, can be greatly recognized to its versatility
and the development of well-defined catalysts. However, taking into account Ru cost and
high end-product purity, easy catalyst separation, recyclability and minimal complex
leaching become crucial criteria for widespread applications of metathesis in organic
synthesis.
Diverse immobilization strategies for metathesis catalysts have been developed;
unfortunately most reports on supported metathesis catalysts describe loss of activity or
barely survive a few recycles.
A practical, inexpensive immobilization strategy for recyclable and reusable catalysts,
with large-scale potential remains thus challenging. It followed that the ‘soft’
immobilization strategy of Hoveyda-Grubbs on silica surfaces is very promising.
However till now we lack the fundamental understanding of its anchoring mechanism. It
is to be expected that a better knowledge of the fundamentals could lead to further
improve the metathesis system (at the level of support and complex), and to an extension
of the unique strategy to similar organometallic complexes useful in other organic
reaction types. Moreover, a further extension of this immobilization strategy towards
highly polar conditions is also greatly desirable.