. . . . . "More concretely, L1 includes, for example, a halogen atom such as a chlorine atom, a bromine atom or an iodine atom; an organic sulfonyl group such as a methanesulfonyl group, an ethanesulfonyl group, a benzenesulfonyl group; and an organic sulfonyloxy group such as a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group, a p-toluenesulfonyloxy group et al." .