Regioselective Synthesis of β- and γ-Thujaplicins

β-Thujaplicin (hinokitiol) 1 and γ-thujaplicin 2, as the first naturally occurring monocyclic tropolone, were regioselectively synthesized from (R)-(+)-limonene, by using different dienyl silyl ether intermediates, 7 and 10, in 18% overall yield via 11 steps and 22% overall yield via 10 steps, respectively.