Synthetic Organic Chemistry Based on Small Ring Compounds

Abstract

Small ring systems are important topics in both organic and inorganic chemistry, and draw considerable attention from both theoretical and preparative perspectives. This review intends to summarize the studies, focusing on the preparative aspects, that have been carried out in our laboratory. Namely, synthesis of (

Asymmetric synthesis of the 2,2,3-trisubstituted cyclopentanone, D-ring fragment of 9,11-secosterols

“…There are also examples where a polysubstituted cyclopentane derivative was constructed via cyclization of an acyclic intermediate 3,4 or via ring expansion from a cyclopropane. 5,12 However, many presented examples deal with racemic compounds only.…”

Applications of 1-Alkenyl-1,1-Heterobimetallics in the Stereoselective Synthesis of Cyclopropylboronate Esters, Trisubstituted Cyclopropanols and 2,3-Disubstituted Cyclobutanones

“…Substituted cyclopropanols exhibit diverse reactivity and are valuable synthetic intermediates 57–60. For instance, they formally act as homoenolates via ring cleavage reactions and readily undergo ring expansion 57.…”

Cycloaddition reactions for antiviral compounds

“…Thus it seems possible that the high stereoselectivity might reflect the severe steric interactions present in the endo transition states T3 and T4 and the exo transition state T2 in comparison with the exo transition state T1. 29 The application of DA cycloaddition reactions to the synthesis of antiviral compounds also finds in the hetero version of these [4 1 2] processes a wide panorama of valuable reactions. 26 The facility of the thermally allowed conrotatory 4π-electrocyclic ring opening of cyclobutenes is known to depend on the electronic nature of the substituents on the cyclobutene ring.…”