This invention relates to a process to functionalize propylene co-oligomer comprising contacting an alkene metathesis catalyst with a heteroatom containing alkene, and a propylene a co-oligomer having an Mn of 300 to 30,000 g/mol comprising 10 to 90 mol % propylene and 10 to 90 mol % of ethylene, wherein the oligomer has at least X % allyl chain ends, where: 1) X=(−0.94 (mol % ethylene incorporated)+100), when 10 to 60 mol % ethylene is present in the co-oligomer, and 2) X=45, when greater than 60 and less than 70 mol % ethylene is present in the co-oligomer, and 3) X=(1.83*(mol % ethylene incorporated)−83), when 70 to 90 mol % ethylene is present in the co-oligomer. This invention also relates to a process to functionalize propylene homo-oligomer comprising contacting an alkene metathesis catalyst with a heteroatom containing alkene, and a propylene homo-oligomer, comprising propylene, wherein the oligomer has: at least 93% allyl chain ends, an Mn of about 500 to about 20,000 g/mol, an isobutyl chain end to allylic vinyl group ratio of 0.8:1 to 1.2:1.0, and less than 100 ppm aluminum.