US 11,840,511 B2
Haloacetaldehyde alkyl 2-cyclopentenyl acetal compound and a process for preparing the same, a process for preparing a (2-cyclopentenyl)acetate ester compound therefrom, and a process for preparing a (2-cyclopentenyl)acetic acid compound therefrom
Miyoshi Yamashita, Joetsu (JP); and Takeshi Kinsho, Joetsu (JP)
Assigned to Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed on Jun. 6, 2022, as Appl. No. 17/805,513.
Claims priority of application No. 2021-096712 (JP), filed on Jun. 9, 2021.
Prior Publication US 2023/0002304 A1, Jan. 5, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. C07C 67/14 (2006.01); C07C 51/09 (2006.01); C07C 67/00 (2006.01); C07C 41/52 (2006.01); C07C 43/313 (2006.01)
CPC C07C 67/14 (2013.01) [C07C 41/52 (2013.01); C07C 43/313 (2013.01); C07C 51/09 (2013.01); C07C 67/00 (2013.01); C07C 2601/10 (2017.05)] 16 Claims
 
1. A process for preparing a (2-cyclopentenyl)acetate ester compound of the following general formula (2):

OG Complex Work Unit Chemistry
wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms, and X1 to X7 represent, independently of each other, a hydrogen atom or a methyl group, with the proviso that one to three among X1 to X7 represent a methyl group and the remaining represent a hydrogen atom,
the process comprising:
subjecting a haloacetaldehyde alkyl 2-cyclopentenyl acetal compound of the following general formula (1):

OG Complex Work Unit Chemistry
wherein R is as defined above, X1 to X7 are as selected in the general formula (2), respectively, and Y represents a halogen atom,
to a dehydrohalogenation reaction in the presence of a base, followed by a rearrangement reaction to form the (2-cyclopentenyl)acetate ester compound (2).