Synthesis of polycyclic structures by Diels-Alder reaction of inner-outer-ring 1,3-bis[(trimethylsilyl)oxy]dienes.

In this paper we describe regioselective one-pot preparations of inner-outer-ring 
1,3-bis[trimethylsilyloxy]dienes and their Diels-Alder reactions with electron-deficient dienophiles. The dienes were prepared in quantitative yield, and the Diels-Alder reactions proceeded smoothly, regioselectively and with good yields, allowing efficient construction of highly functionalized polycyclic skeletons such as naphthofurans, benzofurans and various carbocycles present in natural and non-natural products.