Design and Synthesis of Spirocycles
In this account we disclose a variety of simple strategies demonstrated in our laboratory in the last two decades for the assembly of diverse and intricate molecular frameworks containing spiro linkage(s) by using various metathesis protocols such as ring-closing metathesis (RCM), ring-opening cross-metathesis (ROCM), ring-closing enyne metathesis (RCEM) and ring-rearrangement metathesis (RRM). Also, cycloaddition reactions ([2+2], [4+2] and [2+2+2]) and other key processes such as Claisen rearrangement (CR), Grignard addition, Fischer indolization (FI), Suzuki–Miyaura (SM) cross-coupling and the retro-Diels–Alder (rDA) reaction have been used as key steps to construct spirocycles.