How to find regex pattern in {}

I want find 2 pattern to regex

pattern1 is find pattern2 is {str} find

two case in String value

result

pattern1 = [regex1, regex2] pattern2 = [regex3]

sample String

let str = "I want ()의 \"{regex3}\" find pattern."

pattern1 = "\{\{(.*?)\}\}"

pattern2 = ??