反应详情

Menthol may be condensed with compound 16, 3,4-dihydro-2H-pyran-2-carboxaldeyde in the presence of acid to provide compound 17, 6-menthyloxy-tetrahydro-2H-pyran-2-carboxaldehyde. A Lewis acid or a protic acid may be employed, with protic acids being preferred. Aldehyde 17 may be reduced to an alcohol 19, 6-menthyloxy-tetrahydro-2H-pyran-2-methanol, by catalytic hydrogeneration for example, over Raney nickel or a nobel metal catalyst. Compound 17 may alternatively be reduced to compound 19 using a hydride reducing agent, such as sodium borohydride or lithium aluminum hydride.