Novel fragmentation reaction of 2-alkyl- and 2,4-dialkyl-3-iodo-1-oxocyclohexan-2,4-carbolactones.
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.
Khim
Seock-Kyu
SK
Department of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. seock-kyu_khim@berlex.com
Dai
Mingshi
M
Zhang
Xuqing
X
Chen
Lei
L
Pettus
Liping
L
Thakkar
Kshitij
K
Schultz
Arthur G
AG
D002384:Catalysis; D003500:Cyclization; D003512:Cyclohexanones / Q000737:chemistry*; D007783:Lactones / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
D003512:Cyclohexanones; D007783:Lactones; D008094:Lithium