title: Novel fragmentation reaction of 2-alkyl- and 2,4-dialkyl-3-iodo-1-oxocyclohexan-2,4-carbolactones.
abstract: 2-Alkyl- and 2,4-dialkyl-3-iodo-1-oxocyclohexan-2,4-carbolactones undergo lithium hydroxide- and lithium alkoxide-induced fragmentation reactions to provide butenolides, gamma-hydroxycyclohexenones, and/or gamma-butyrolactones. In general, product distribution is governed by two factors: (1) the nature of nucleophiles and (2) the steric bulkiness of the substituents at C-2 and C-4 of the cyclohexanones. Lithium hydroxide-induced fragmentation provides butenolides and gamma-hydroxycyclohexenones. In contrast, lithium alkoxide-promoted fragmentation results in predominantly 5-substituted gamma-butyrolactones along with a small amount of butenolides in limited cases. Fragmentation products induced by lithium hydroxide are largely influenced by the steric bulkiness of the substituents at C-2 and C-4 of the cyclohexanone ring. The bulky substituents render the exclusive formation of butenolides.
authors.affiliation: Department of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. seock-kyu_khim@berlex.com
authors.forename: Seock-Kyu
authors.initials: SK
authors.lastname: Khim
authors.forename: Mingshi
authors.initials: M
authors.lastname: Dai
authors.forename: Xuqing
authors.initials: X
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Liping
authors.initials: L
authors.lastname: Pettus
authors.forename: Kshitij
authors.initials: K
authors.lastname: Thakkar
authors.forename: Arthur G
authors.initials: AG
authors.lastname: Schultz
mesh_terms: D002384:Catalysis; D003500:Cyclization; D003512:Cyclohexanones / Q000737:chemistry*; D007783:Lactones / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D003512:Cyclohexanones; D007783:Lactones; D008094:Lithium