IF NOT EXISTS statement postgresql throwing syntax error

I am trying to insert some data into a table, but only if the table is empty. So this is what i tried.

IF EXISTS (select * from ${schema}.JITenant) THEN ELSE <inster_statements> END IF;

Error log shows:

SQL State  : 42601
Error Code : 0
Message    : ERROR: syntax error at or near "IF"
Position   : 1
Line       : 7
Statement  : IF EXISTS (select * from migrate.JITenant) THEN
ELSE
INSERT into migrate.JITenant 

I cant figure out what the problem is.