The development of two efficient strategies for the synthesis of AZD4407 is reported, both of which are considered suitable for large-scale manufacture. In the first approach, 3-bromothiophene is coupled with (2S)-2- methyltetrahydropyran-4-one using Grignard chemistry. Following hydroxyl protection and lithiation at thiophene C-2, reaction with a protected 5-mercapto-1-methyl-1,3-dihydro-indol-2-one derivative bearing a leaving group on sulphur provides AZD4407 after acid-catalysed deprotection and epimerisation. The second approach starts from 2,4-dibromothiophene, which undergoes a selective Grignard exchange reaction at C-2 followed by reaction with similar protected mercapto-oxindole derivatives. Reprotection of the oxindole ring, followed by a second Grignard exchange, and reaction with (2S)-2- methyltetrahydropyran-4-one provides AZD4407 after acid-catalysed deprotection and epimerisation.