The novel tetracyclic sesquiterpenoid (+)-cyclomyltaylan-5α-ol 1 has been synthesized starting from (S)-(+)-Hajos-Wiechert ketone analogue 3via SmI2-promoted reductive cyclization as a key step. Thus, the absolute configuration has been established to be 2R, 3R, 4R, 5S, 6R, 7R (cyclomyltaylane numbering) as depicted in structure 1.