Everything I've read suggests that sugars do not caramelize during normal wort boiling. The temperature is too low.
Well, if it looks like a duck, and quacks like a duck. . .
"MAILLARD browning reactions involve simple sugars and amino acids and simple peptides. They proceed during the kilning of malt, and during wort boiling. They begin to occur at lower temperatures and at higher dilutions than caramelisation. The rate can increase by 2-3 times for each 10C rise in temperature. However even long term storage of malt extract will Maillard-brown at room temperature. Prize winning dark beers have been coloured by this method as they had none of the harshness of some high temperature Maillard reactions in roasted malts.
Maillard reactions have three basic phases. 1/The initial reaction is the condensation of an amino acid with a simple sugar, which loses a molecule of water to form N-substituted aldosylamine. This is unstable and undergoes the famous "Amadori rearrangement" to form "1-amino-1-deoxy-2-ketoses" (known as "ketosamines") which can undergo complex subsequent dehydration, fission and polymerization reactions.
But wait, I here you say! "A sugar loses a water molecule and undergoes further dehydration?" Sounds like a Caramelisation reaction?
*And it is!* One of the reasons Caramel and Maillard reactions are confused in brewing and food processing literature is that one of the Maillard paths is a simple Caramel reaction, catalysed by amino acids. But now in Maillard, there are a few guys called Schiff, Amadori and Strecker in your beer!"