This is an interesting question, and after mostly failing to find recent literature I've become fascinated at why this topic is not more heavily studied. It looks like a field ripe for disruption by new ideas and approaches.
I'm not convinced that procrastination is any different in those diagnosed with ADHD than in neurotypicals. As with many psychiatric diagnoses, behaviors are described in the DSM but mechanisms are usually unknown. Without knowing any mechanism (hand-waving a probable weakness of connection between prefrontal areas and motor areas, but no idea what may weaken it) it's hard to say whether an unknown mechanism in ADHD differs from an unknown mechanism in everyone else, or even that the distinction between ADHD and normal has clear boundaries. I'd really appreciate the education of being shown evidence I'm wrong here, but I've seen heated debates over defining ADHD, and Stack Exchange doesn't do extended back-and-forth discussions.
The slope of the curve representing what I've known as "delay discounting" (also called "time preference") was described by Green and Myerson and has been associated with ADHD, drug abuse and gambling, and lower socioeconomic status. But I don't see this as a mechanism, just another way to quantify the behavior.
The nature of procrastination by Piers Steel and Longitudinal study of procrastination, performance, stress, and health by Roy Baumeister seem to be the most relevant (highly cited) descriptions of procrastination, and both are over a decade old. Some intervention articles I've found are ADHD outcomes for children treated in community based pediatric settings by Jeffrey Epstein (not that one), et al and Academic interventions for academic procrastination by Zacks and Hen, but I can't find anything on interventions that seems to be highly cited and well-accepted.
I disclose that I often procrastinate on StackExchange. I'm currently reading and writing about procrastination rather than working on analyses I need done asap. :(