In general, journals with a high impact factor tend to be more selective and therefore have a high rejection rate as well. However, this is not always true.
Some journals with a low impact factor have a high rejection rate; for example, new journals aspiring to be the best in their field have a low impact factor but they can be extremely selective. Conversely, some journals with a high impact factor may not be very selective; for example, the open-access journal PLoS One has an impact factor above 4, but its rejection rate is relatively low (30%) because it aims to publish a large volume of research.