In 1951 he won the Prix de Rome with the cantata Et l'homme se vit les portes rouvrir.
During his stay at the Villa Medici in Rome he wrote the First Concerto for String Orchestra and the Ode for a Tragic Death.
In addition to several operas, one symphony and chamber works Chaynes composed numerous concertos, etc.
In 1966 he composed a concerto for organ, string orchestra, timpani and percussion for Marie-Claire Alain.
His Piano Concerto was premiered in 1967 by Yvonne Loriod, the wife of Olivier Messiaen.