depends what you mean by "in synch". Like in synch to a femtosecond, or just repeatably in sych so the rising edges are within say 20 nanoseconds of each other.
The synch pulse you show can be generated by a divide by two circuit (flip flop) counting the clock, and you can enable a single pulse to output on the counter chip or possibly by adding a fast AND gate at the output of the counter. You could add some some capacitive delay to the clock output, to get the clock and synch pulse to match right up.
in other words, use one 555 chip, and one flipflop, and some sort of gate to only output ONE synch pulse when it is wanted.