The non-metathetic role of Grubbs' carbene complexes: from hydrogen-free reduction of α,β-unsaturated alkenes to solid-supported sequential cross-metathesis/reduction.

An efficient and high-yielding "hydrogen-free" reduction of α,β-unsaturated alkenes was carried out employing Grubbs' catalyst in a non-metathetic role and Et(3)SiH. Conditions were optimized under microwave irradiation. Application to the solid-phase organic synthesis allows a facile construction of sp(3)-sp(3) carbon bonds through a sequential cross metathesis/olefin reduction.