Processes for preparing alpha-necrodyl compounds and processes for preparing gamma-necrodyl compounds

Patent metadata

Field	Value
Publication number	US-11370741-B2
Application number	US-202117378952-A
Country	US
Kind code	B2
Filing date	Jul 19, 2021
Priority date	Jul 22, 2020
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

The present invention provides processes for preparing an α-necrodyl compound of the following general formula (3): wherein R2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting a 3, 5, 5-trimethyl-3-cyclopentene compound of the following general formula (1): wherein R2 is as defined above, and X represents a leaving group, to a nucleophilic substitution reaction with a methylating agent of the following general formula (2): wherein M represents Li, MgZ1, ZnZ1, Cu, CuZ1, or CuLiZ1, and Z1 represents a halogen atom or a methyl group, to form the α-necrodyl compound (3). The present invention further provides processes for preparing γ-necrodyl compounds of the following general formula (4): wherein R2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).

First claim

The invention claimed is:

1. A process for preparing an α-necrodyl compound of the following general formula (3):

wherein R 2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, and a bold unwedged bond and a hashed unwedged bond represent a relative configuration,
the process comprising:
subjecting a 3, 5, 5-trimethyl-3-cyclopentene compound of the following general formula (1):

wherein R 2 is as defined above, X represents a leaving group, and hashed unwedged bonds represent a relative configuration,
to a nucleophilic substitution reaction with a methylating agent of the following general formula (2):
CH 3 -M  (2)

wherein M represents Li, MgZ 1 , ZnZ 1 , Cu, CuZ 1 , or CuLiZ 1 , and Z 1 represents a halogen atom or a methyl group,
to form the α-necrodyl compound (3).

2. The process for preparing the α-necrodyl compound (3) according to claim 1 , wherein the 3,5,5-trimethyl-3-cyclopentene compound (1) is (1RS, 2SR)-(3, 5, 5-trimethyl-2-isobutyryloxy-3-cyclopentenyl)methyl isobutyrate of the following formula (1A):

wherein i Pr represents an isopropyl group, and hashed unwedged bonds represent a relative configuration, and
the α-necrodyl compound (3) is (1RS, 4RS)-(3, 4, 5, 5-tetramethyl-2-cyclopentenyl)methyl isobutyrate of the following formula (3A):

wherein the bold unwedged bond and the hashed unwedged bond represent a relative configuration.

3. A process for preparing a γ-necrodyl compound of the following general formula (4):

wherein R 2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms,
the process comprising:
the process for preparing the α-necrodyl compound (3) according to claim 1 , and
subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).

4. The process for preparing the γ-necrodyl compound (4) according to claim 3 ,
wherein the γ-necrodyl compound (4) is (1RS)-(2, 2, 3, 4-tetramethyl-3-cyclopentenyl)methyl isobutyrate of the following formula (4A):

5. The process for preparing the α-necrodyl compound (3) according to claim 1 , the process further comprising:
subjecting (1RS,2SR)-(2-hydroxy-3, 5, 5-trimethyl-3-cyclopentenyl)methanol of the following formula (5C):

wherein hashed unwedged bonds represent a relative configuration,
to an esterification reaction, a combination of an esterification reaction with a halogenation reaction, or a combination of an esterification reaction with a sulfonylation reaction to form the 3,5,5-trimethyl-3-cyclopentene compound (1).

6. The process for preparing the α-necrodyl compound (3) according to claim 5 , the process further comprising:
subjecting a 3, 5, 5-trimethyl-2-oxo-3-cyclopentene-1-carboxylate ester compound of the following general formula (6):

wherein R 1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms,
to a reduction reaction to form (1RS,2SR)-(2-hydroxy-3,5,5-trimethyl-3-cyclopentenyl)methanol (5C).

7. The process for preparing the α-necrodyl compound (3) according to claim 5 , the process further comprising:
converting a 3, 5, 5-trimethyl-2-oxo-3-cyclopentene-1-carboxylate ester compound of the following general formula (6):

wherein R 1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, into a corresponding carboxylic acid, and
subjecting the carboxylic acid thus obtained to a reduction reaction to form (1RS,2SR)-(2-hydroxy-3,5,5-trimethyl-3-cyclopentenyl)methanol (5C).

8. A process for preparing a γ-necrodyl compound of the following general formula (4):

wherein R 2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms,
the process comprising:
the process for preparing the α-necrodyl compound (3) according to claim 5 , and
subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).

9. (2-Hydroxy-3, 5, 5-trimethyl-3-cyclopentenyl)methanol of the following formula (5):

10. A process for preparing a γ-necrodyl compound of the following general formula (4):

wherein R 2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms,
the process comprising:
the process for preparing the α-necrodyl compound (3) according to claim 6 , and
subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).

11. A process for preparing a γ-necrodyl compound of the following general formula (4):

wherein R 2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms,
the process comprising:
the process for preparing the α-necrodyl compound (3) according to claim 7 , and
subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).

Assignees

• Shinetsu Chemical Co

Inventors

• Watanabe Tomohiro
• Kinsho Takeshi
• Nagae Yusuke

Classifications

• C07C67/293

  by isomerisation; by change of size of the carbon skeleton · CPC title

• C07C2601/10

  the ring being unsaturated · CPC title

• C07C33/12 Primary

  containing five-membered rings · CPC title

• C07C29/147

  of carboxylic acids or derivatives thereof · CPC title

• C07C67/343 Primary

  by increase in the number of carbon atoms · CPC title