i beleive , you CANNOT TRUNCATE via synonym
first,
A synonym refers to object belonging others and you are not the owner of the object.
becuase
You cannot create synonym with the same name as the object in same schema
else
you need to have a different names for table and synonymn in the same schema.
[i]
ORA-01471: cannot create a synonym with same name as object [/i]
TRUNCATE TABLE DDL is valid only for tables, clusters
there is NO OPTION for a synonym.
[i]
ERROR at line 1:
ORA-00942: table or view does not exist
[/i]