Natalie Cole, the Grammy Award-winning singer whose hits included “Inseparable,” “Pink Cadillac” and “Unforgettable,” a virtual duet with her father, Nat King Cole, that topped the Billboard charts in 1991, died in Los Angeles on Thursday. She was 65. Ms. Cole had undergone a kidney transplant in 2009 and had suffered from other ailments recently, forcing the cancellation of a series of tour dates in November and December. Ms. Cole — who was raised around jazz royalty in the company of her father and her mother, Maria Hawkins Cole, a singer who worked with Duke Ellington and Count Basie — came into her own as a singer in the 1970s by staking out her own territory in R&B.