Cyclopentane Formation from Flexible Precursors Using Samarium(II) Reagents

This study presents three efficient methods for five‐membered ring carbocycle synthesis using samarium(II) reagents. Simple organic starting materials engage in intramolecular Reformatsky aldol, enolate alkylation, and pinacol cyclizations. A promising lead result has also been established demonstrating enantioselectivity in a chiral ligand controlled Reformatsky aldol reaction. Three efficient methods for five‐membered ring carbocycle synthesis have been developed from simple starting materials using samarium(II) reagents. A Reformatsky aldol reaction proceeded efficiently with samarium(II) iodide using lithium bromide as an additive. A new intramolecular alkylation of a samarium enolate was realized with a pendant sulfonate ester leaving group. Pinacol cyclization of a simple diketone was also demonstrated giving a diol product in high stereoselectivity. A promising lead result has been established demonstrating enantioselectivity in a chiral ligand controlled Reformatsky aldol reaction