C++11: reinterpreting array of structs as array of struct's member

Consider the following type:

struct S
{
    char v;
};

Given an array of const S, is it possible to, in a standard conformant way, reinterpret it as an array of const char whose elements correspond to the value of the member v for each of the original array's elements, and vice-versa? For example:

const S a1[] = { {'a'}, {'4'}, {'2'}, {'\0'} };
const char* a2 = reinterpret_cast< const char* >(a1);

for (int i = 0; i < 4; ++i)
    std::cout << std::boolalpha << (a1[i].v == a2[i]) << ' ';

Is the code above portable and would it print true true true true? If not, is there any other way of achieving this?

Obviously, it is possible to create a new array and initialize it with the member v of each element of the original array, but the whole idea is to avoid creating a new array.