public class Company
{

Public Company()
{
Products = new List<Product>();

}
[Key]
public int Id { get; set; }

[Required]
public string Name { get; set; }

public List<Product> Products { get; set; }
}
public class Product
{
    [Key]
    public int Id { get; set; }

    [Required]
    public string Name { get; set; }

}

Post: ~odata/Company(1)/Products with body as List of products json.
body:[{"Name":"Product1"},{"Name":"Product2"}]