The reaction of 2-chloromethyl-3-(2-methoxyethoxy)prop-1-ene (1) with an excess of lithium powder and a catalytic amount of naphthalene (2.5%) in the presence of a carbonyl compound (E 1 =R 1 R 2 CO) in THF at -78 to 0 o C, followed by treatment with an epoxide [E 2 =R 3 R 4 C(O)CHR 5 ] at 0 to 20 o C leads, after hydrolysis, to the expected unsaturated diols 2. When some compounds 2 (2e-h) are successively hydroborated (BH 3 .THF) and oxidised (33% H 2 O 2 and then PCC), the expected perhydrofuropyrans 3e-h are isolated directly.