Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

One of these functional groups can be added to a terminal alkyne, frequently catalyzed by copper(I), in what has been referred as the paradigm of click chemistry by K. Barry Sharpless. That is a 1,3-dipolar reaction known as the Huisgen cycloaddition, which results in a 1,2,3-triazole. One of these is reacted with tri-phenyl-phosphine in the Staudinger reaction; that reaction results in tri-phenyl-phosphine oxide and a reduced version of this functional group. These are defined as compounds containing the group N3 with one nitrogen attached to a parent structure. FTP, name this functional group which can be reduced to amines.
Science