Preparation of γ-trimethylsilylallyldibutylstannane grafted on solid support: a clean and easily recyclable reagent for the synthesis of 2,6-disubstituted dihydropyrans

The synthesis of the γ-trimethylsilyldibutylallylstannane grafted on an insoluble macroporous polymer is reported. This bimetallic reagent was treated with aldehydes in the presence of indium trichloride to afford in good yields both symmetrical and unsymmetrical cis-2,6-disubstituted dihydropyrans, practically uncontaminated with organotin residues (less than 20 ppm). The potential for regeneration and reuse of this supported bimetallic reagent is pointed out.