Treatment of tertiary 1,4- and 1,5-diols with cerium ammonium nitrate at room temperature led to the corresponding tetrahydrofuran and tetrahydropyran derivatives in high yield and stereoselectivity. Utilizing this methodology, manoyl oxide (25a) and a variety of fragrant compounds, such as linalool oxide (8), caparrapi oxide (12), ambrox (14) and other related amber-gris-type odorants have been synthesized; 16 examples are described.