Get c# object list from response.Content.ReadAsStringAsync()

You need to await the task like so:

var result = await response.Content.ReadAsStringAsync();

Danger of using var, as now it inferred the type as Task<string>. If you had tried:

string result = response.Content.ReadAsStringAsync();

It would have immediately given you an error that it can't cast Task<string> to string.

EDIT: The other error you have is that you are trying to deserialize the JSON into an object when it is actually an array.

List<BusinessUnit> businessunits = JsonConvert.DeserializeObject<List<BusinessUnit>>(result);

You could try this:

IEnumerable<BusinessUnit> result = await response.Content.ReadAsAsync<IEnumerable<BusinessUnit>>();

Saludos.