Jm. Campelo et al., SPANISH SEPIOLITE CLAY AS A NEW HETEROGENEOUS CATALYST FOR THE TETRAHYDROPYRANYLATION OF ALCOHOLS AND PHENOLS, Synthetic communications, 24(10), 1994, pp. 1345-1350
OH-protection of alcohols and phenols by heating the hydroxylated comp
ound with 3,4-dihydro-2H-pyrane in the presence of a readily available
and inexpensive spanish sepiolite heterogeneous acid clay catalyst is
described. Isolated yields, not optimized, were in the range 29-99%.