No, sucrose is split practically instantaneously into fructose and sucrose in the gut; you have an enzyme, sucrase, specifically to do it. The process is complete seconds after sucrose enters your small intestine. The process of getting the glucose into your bloodstream takes far longer. Where did you get this idea? I've heard other people say it too; there must be a source for it.

You said, "So excessive consumption of high fructose corn syrup is more harmful than excessive consumption of plain corn syrup or of sugar." This appears to be plainly false.