Boston Mayor Thomas M. Menino fired a broadside at the city’s teachers’ union in a speech delivered this afternoon, saying that the union’s refusal to reach a contract deal with the city was keeping it from putting the right teachers in the right classrooms. “Unfortunately, we must start planning for next year with the old process in place. A process that puts teachers with mis-matched skills in mis-matched classrooms. That’s wrong,” Menino said in remarks prepared for delivery at the Boston Municipal Research Bureau’s 80th annual meeting. Menino said a new teacher contract “must provide more flexibility so that all Boston kids have access to an outstanding education in all of our schools,” saying a signature issue in education reform was “the ability for principals to place talented teachers where they are needed most.”