EP-4116308-B1 - METHOD FOR PRODUCING NAPHTYLSILOLE, NAPHTHYLSILOLE CONTAINING HETEROCYCLIC GROUP, AND GRAPHENE NANORIBBON CONTAINING HETEROCYCLIC GROUP

EP4116308B1EP 4116308 B1EP4116308 B1EP 4116308B1EP-4116308-B1

Inventors

ITAMI, KENICHIRO
ITO, HIDETO
MATSUSHIMA, Kaho
MURAKAMI, KAZUO
NAKATSUJI, Hidefumi
ISHIDA, SHUNSUKE

Dates

Publication Date: 20260513
Application Date: 20210225

Claims (1)

A method for producing a compound represented by formula (3): wherein R 1a and R 1b are the same or different and represent a hydrogen atom, an alkyl group, a cycloalkyl group, a (poly)ether group, an ester group, a halogen atom, an aromatic hydrocarbon group, or a heterocyclic group; R 1a and R 1b are optionally bound to each other to form a ring; R 2' represents an aromatic hydrocarbon ring or a heterocyclic ring; R 3a and R 3b are the same or different and represent an optionally branched C 1 -C 4 alkyl group or a phenyl group; the method comprising the following steps in this order: a step of reacting a compound represented by formula (1): wherein R 1a and R 1b are as defined above; R 2 represents an aromatic hydrocarbon group or a heterocyclic group; and X represents a bromine atom or an iodine atom with a lanthanide- and lithium-containing ate complex to produce a lanthanide complex of the compound represented by formula (1); and a step of reacting the lanthanide complex with a silyl compound represented by formula (2): R 3a R 3b SiCl 2 (2) wherein R 3a and R 3b are as defined above.

Description

Technical Field The present invention relates to a method for producing a naphthylsilole that is for use as a starting material for a graphene nanoribbon (hereinafter sometimes referred to as "GNR"). Background Art Graphene nanoribbons (GNRs) are materials that are expected to find application in semiconductors, solar batteries, transparent electrodes, high-speed transistors, organic EL devices, and the like. Methods for producing GNRs are roughly classified into two methods: the top-down method and the bottom-up method. The latter method, i.e., the bottom-up method, is particularly attractive in terms of its ability to synthesize a large amount of GNRs with precise control of the edge structure and width thereof. The present inventors focused their attention on the production of GNRs by the bottom-up method, and performed extensive research on the method for producing GNRs. As a result, the inventors found a production method using a naphthylsilole as a starting material as a method for producing GNRs with fewer steps, while suppressing side reactions (Patent Literature (PTL) 1). Citation List Patent Literature PTL 1: WO2020/184625PTL 2: US2017/141331 (WO2016/021815) Summary of Invention Technical Problem PTL 1 mentioned above discloses that a naphthylsilole, a starting material for GNR, can be produced, for example, by a method comprising reacting a compound represented by formula (9): (wherein R represents a substituent)with n-butyl lithium (n-BuLi) andthen reacting the resulting compound with dimethylsilyl chloride to obtain a silyl compound represented by formula (10): (wherein R is as defined above), andcyclizing the silyl compound using di-tert-butylperoxide ((t-BuO)2) (Synthesis Example 2 of PTL 1). However, this production method must use dimethylsilyl chloride, which has a very low flash point and a very low boiling point; and also must use di-tert-butylperoxide, which is a self-reactive organic peroxide. Therefore, in the industrial implementation thereof, this production method is not considered to be fully safe in terms of disaster prevention. PTL 2 mentioned above discloses a method for preparing W-6: via intramolecular cyclisation of W-5: using RhCl (PPh3)3 (cf. PTL 2, par. [0116]). An object of the present invention is to provide a method for more safely producing a naphthylsilole for use as a starting material for GNR. Solution to Problem The present inventors conducted extensive research to solve the above problem. As a result, the inventors found that the following method is capable of producing a naphthylsilole more safely from a relatively low-risk compound. More specifically, the present invention includes the following inventions. Item 1. A method for producing a compound represented by formula (3): (wherein R1a and R1b are the same or different and represent a hydrogen atom, an alkyl group, a cycloalkyl group, a (poly)ether group, an ester group, a halogen atom, an aromatic hydrocarbon group, or a heterocyclic group; R1a and R1b are optionally bound to each other to form a ring; R2' represents an aromatic hydrocarbon ring or a heterocyclic ring; R3a and R3b are the same or different and represent an optionally branched C1-C4 alkyl group or a phenyl group) ; the method comprising the following steps in this order: a step of reacting a compound represented by formula (1) : (wherein R1a and R1b are as defined above; R2 represents an aromatic hydrocarbon group or a heterocyclic group; and X represents a bromine atom or an iodine atom) with a lanthanide- and lithium-containing ate complex to produce a lanthanide complex of the compound represented by formula (1); anda step of reacting the lanthanide complex with a silyl compound represented by formula (2): R3aR3bSiCl2 (2) (wherein R3a and R3b are as defined above). The following aspects (Items 2 to 8) are not according to the invention and are present for illustration purposes only. Item 2. A compound represented by formula (1): (wherein R1a and R1b are the same or different and represent a hydrogen atom, an alkyl group, a cycloalkyl group, a (poly)ether group, an ester group, a halogen atom, an aromatic hydrocarbon group, or a heterocyclic group; R1a and R1b are optionally bound to each other to form a ring; R2 represents an aromatic hydrocarbon group or a heterocyclic group; and X represents a bromine atom or an iodine atom). Item 3. A method for producing the compound of Item 2, comprising reacting a compound represented by formula (4): (wherein R1a, R1b, and X are as defined above; R4 represents an optionally branched C1-C4 alkyl group, an optionally branched C1-C4 halogenated alkyl group, or an aromatic hydrocarbon group) with a compound represented by formula (5) R2MgBr (5) (wherein R2 is as defined above) . Item 4. A compound represented by formula (4): (wherein R1a and R1b are the same or different and represent a hydrogen atom, an alkyl group, a cycloalkyl group, a (poly)ether group, an ester g