Method for producing peptide compound, protective group-forming reagent, and condensed polycyclic compound

A protective group-forming reagent comprising:

• a compound represented by Formula (1),
• in Formula (1),
• Y1 represents —OR17, —NHR8, —SH, or a halogen atom, where R17 represents a hydrogen atom, an active ester-type carbonyl group, or an active ester-type sulfonyl group, and R18 represents a hydrogen atom, an alkyl group, an arylalkyl group, a heteroarylalkyl group, or a 9-fluorenylmethoxycarbonyl group,
• Y2 represents —N(R110)—, —O—, —S—, —CR100═CR101—, —CR102R103—CR104R105—, or —CR106R107—, where R110 represents RA or an alkyl group, and R100 to R107 each independently represent a hydrogen atom or an alkyl group,
• R1 to R8 each independently represent RA, a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group,
• at least one of R1 to R8 or Y2 has RA,
• RA represents an aliphatic hydrocarbon group or an organic group having an aliphatic hydrocarbon group, and
• the number of carbon atoms in at least one aliphatic hydrocarbon group is 12 or more,
• provided that, RA does not have a silyl group and a hydrocarbon group having a silyloxy structure.

A condensed polycyclic compound represented by Formula (1a),

• in Formula (1a),
• Ya1 represents —ORa17, —NHRa18, —SH, or a halogen atom, where Ra17 represents a hydrogen atom, an active ester-type carbonyl group, or an active ester-type sulfonyl group, and Ra18 represents a hydrogen atom, a linear or branched alkyl group having 10 or less carbon atoms, an arylalkyl group, a heteroarylalkyl group, or a 9-fluorenylmethoxycarbonyl group,
• Ya2 represents —N(R110)—, —O—, —S—, —CRa100═CRa101—, —CRa102Ra103—CRa104Ra105—, or —CRa106Ra107—, where R110 represents RA or an alkyl group, and Ra100 to Ra107 each independently represent a hydrogen atom or an alkyl group,
• Ra1 to Ra8 each independently represent RA, a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms,
• at least one of Ra2, . . . , or Ra7 has RA,
• RA represents an aliphatic hydrocarbon group or an organic group having an aliphatic hydrocarbon group, and
• the number of carbon atoms in at least one aliphatic hydrocarbon group is 12 or more,
• provided that, RA does not have a silyl group and a hydrocarbon group having a silyloxy structure.