re-aging single malt in oak barrel?
 

I have recently purchaced several small oak barrels to age/mature brazilian cachaca with additional spices added. I am wondering if commercially available, bottled, single malt scotch would further age and mature in character if it were placed into these oak casks?

Sure, but you may not like what it picks up from the barrels. Only one way to find out. If you want to get scientific, try one bourbon barrel, one sherry, and one peated whisky to age. See what happens after about 6 months, and every couple months after. Maybe you'll age a great one.
Cheers!