Process for preparing a 5-alken-1-yne compound, (6z)-1,1-dialkoxy-6-nonen-2-yne compound, (2e,6z)-2,6-nonadienal and (2e)-cis-6,7-epoxy-2-nonenal, and 1,1-dialkoxy-6-nonen-2-yne compound

A process for preparing a 5-alken-1-yne compound of the following formula (4):

• Y—Z—CR1═CR2—(CH2)2—C≡CH (4)
• in which Y in formula (4) represents a hydrogen atom or a hydroxyl group, Z represents a divalent hydrocarbon group having from 1 to 15 carbon atoms, and R1 and R2 represent, each independently, a hydrogen atom or a monovalent hydrocarbon group having from 1 to 6 carbon atoms or bond together to form a divalent hydrocarbon group having from 1 to 6 carbon atoms, R1-R2,
• the process comprising at least steps of:
• subjecting (i) an alkenylmagnesium halide compound prepared from a haloalkene compound of the following formula (1):
• Y—Z—CR1═CR2—(CH2)2—X1 (1)
• in which Y, Z, R1 and R2 are as defined above and X1 represents a halogen atom, and (ii) an alkyne compound of the following formula (2):
• X2—C≡C—Si(R3)(R4)(R5) (2)
• in which X2 represents a halogen atom, R3 represents a hydrogen atom or a monovalent hydrocarbon group having from 1 to 6 carbon atoms, and R4 and R5 represent, each independently, a monovalent hydrocarbon group having from 1 to 6 carbon atoms or bond together to represent a divalent hydrocarbon group having from 2 to 6 carbon atoms, R4-R5, to a coupling reaction to form a silane compound of the following formula (3):
• Y—Z—CR1═CR2—(CH2)2—C—Si(R3)(R4)(R5) (3)
• in which Y, Z, R1, R2, R3, R4, and R5 are as defined above;
• and
• subjecting the silane compound (3) to a desilylation reaction to form the 5-alken-1-yne compound (4).