Method for producing fluorine-containing compound and method for producing copolymer

This method for producing a fluorine-containing compound is a method for producing a compound (30) having a partial structure (3) by an insertion reaction in which a compound (20) is inserted into a compound (10) having a partial structure (1) in the presence of a specific ionic catalyst containing a monovalent anion and a counter cation. In the formula, * represents a bond, and X1 and R1-R4 each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, or an optionally substituted organic group having 1-20 carbon atoms. 含氟化合物的制造方法为通过在特定的包含一价阴离子和抗衡阳离子的离子型催化剂的存在下、向具有部分结构(1)的化合物(10)中插入化合物(20)的插入反应而制造具有部分结构(3)的化合物(30)的方法。式中，*：键，X1和R1～R4：各自独立地表示氢原子、氟原子、氯原子或可以具有取代基的碳原子数为1～20的有机基团。