Heteroleptic phosphines (R2PR1) are a class of essential ligands for inorganic and organometallic chemistry. However, the syntheses of these phosphines are often fraught with laborious synthetic hurdles. Consequently, a renewed interest in innovative synthetic methods to access heteroleptic phosphines is emerging. This Perspective presents an overview of modern synthetic approaches to heteroleptic phosphines as well as a discussion of the strengths and limitations of these synthetic methods. A major emphasis is placed on simple and direct routes to phosphines and significant synthetic innovations for P–C bond-forming reactions.
