Ring Contraction Reactions in the Total Synthesis of Biologically Active Natural Products

摘要: Strategic reactions in synthetic organic chemistry are those that increase the molecular complexity of starting material. Particularly important transformations where new carbon–carbon bonds formed. Although during a ring contraction number is conserved, reorganization skeleton may occur with high level selectivity leading to product not easily accessed by other methods. Even highly strained systems can be obtained using Favorskii and Wolff rearrangements. Additionally, approach opens applications for chiral pool readily available materials. This chapter presents as an efficient tool stereoselective synthesis biologically active natural products. The discussed rearrangement, oxidative rearrangements, thermolysis aryliodonium ylides, rearrangements through cationic radical intermediates. Keywords: ring contraction; total synthesis; rearrangement; CC bond formation; hypervalent iodine; stereoselective synthesis; reorganization skeleton; Favorskii rearrangement; Wolff rearrangement; oxidative rearrangement; thermolysis; cationic intermediate; radical intermediate