Provided is a method with which it is possible to produce a polyalkenylphenol compound having a narrow molecular weight distribution and low viscosity at high purity and high yield. A poly 2-alkenyl aromatic ether compound having two or more phenol skeletons is subjected to Claisen rearrangement in the presence of a phenol or naphthol compound.

A monomer for a hardmask composition is represented by the following Chemical Formula 1, ##STR00001##

A monomer for a hardmask composition is represented by the following Chemical Formula 1, ##STR00001##

Provided are a monofunctional phenolic compound used for producing an active ester resin capable of forming a cured product having excellent dielectric properties and excellent heat resistance, an active ester resin and a method for producing the active ester resin, and a thermosetting resin composition and a cured product of the thermosetting resin composition. Specifically, provided are a monofunctional phenolic compound including one or more vinylbenzyl groups and an active ester resin including a vinylbenzyl structure attached to a terminal group of the molecular chain and derived from the monofunctional phenolic compound. The vinylbenzyl structure preferably includes a vinylbenzyl-modified aryloxycarbonyl group.

Provided are a monofunctional phenolic compound used for producing an active ester resin capable of forming a cured product having excellent dielectric properties and excellent heat resistance, an active ester resin and a method for producing the active ester resin, and a thermosetting resin composition and a cured product of the thermosetting resin composition. Specifically, provided are a monofunctional phenolic compound including one or more vinylbenzyl groups and an active ester resin including a vinylbenzyl structure attached to a terminal group of the molecular chain and derived from the monofunctional phenolic compound. The vinylbenzyl structure preferably includes a vinylbenzyl-modified aryloxycarbonyl group.

A vinylbenzylated phenol compound represented by General Formula (1) below is provided. ##STR00001##
(In General Formula (1), Ar.sup.0 is a bifunctional phenol compound residue having one or more monocyclic or polycyclic aromatic nuclei, R.sup.1 to R.sup.5 may be the same or different and are each hydrogen or a methyl group, and p is an integer of 1 to 4.)

A vinylbenzylated phenol compound represented by General Formula (1) below is provided. ##STR00001##
(In General Formula (1), Ar.sup.0 is a bifunctional phenol compound residue having one or more monocyclic or polycyclic aromatic nuclei, R.sup.1 to R.sup.5 may be the same or different and are each hydrogen or a methyl group, and p is an integer of 1 to 4.)

A vinylbenzylated phenol compound represented by General Formula (1) below is provided. ##STR00001##
(In General Formula (1), Ar.sup.0 is a bifunctional phenol compound residue having one or more monocyclic or polycyclic aromatic nuclei, R.sup.1 to R.sup.5 may be the same or different and are each hydrogen or a methyl group, and p is an integer of 1 to 4.)

The present application describes process for preparing an ortho-allylated hydroxy aryl compounds such as compounds of Formula (I) by reacting an allylic alcohol with a hydroxy aryl compound in the presence of aluminum compound selected from alumina and aluminum alkoxides and in a non-protic solvent wherein at least one carbon atom ortho to the hydroxy group in the hydroxy aryl compound is unsubstituted.

##STR00001##

The present application describes process for preparing an ortho-allylated hydroxy aryl compounds such as compounds of Formula (I) by reacting an allylic alcohol with a hydroxy aryl compound in the presence of aluminum compound selected from alumina and aluminum alkoxides and in a non-protic solvent wherein at least one carbon atom ortho to the hydroxy group in the hydroxy aryl compound is unsubstituted.

##STR00001##