Singapore is not your ordinary low-tax center. One would say Singapore is not a low-tax center at all. A corporate tax at the rate of 17% (as of 2019) is imposed upon profits that are earned in, derived from or are received in Singapore by Singapore resident companies (which means incorporated, managed and controlled from Singapore). On the other hand, all foreign earned profits, or earnings that derive from sources outside Singapore, are free from corporation tax.
Just to reiterate on the last point: A private Singaporean company that holds and manages income producing assets outside Singapore can earn profits tax-free, without incurring any liability in Singapore to pay corporation tax.