Craft Commerce Trigger Event to Re-save All Products
There are probably many approaches, but you could write a simple console command (great guide here: https://spin.atomicobject.com/2015/06/16/craft-console-plugin/) in a plugin to do this.  

Here's one I prepared earlier to use as an example...in my case I am doing this because I am using a pre-parse field that pulls in some external markdown content, but the principle is the same (assuming re-saving the entries updates the title field as you hope - but should take only a few mins to try!) - you'll need to adapt for commerce (Commerce_Product I think):

&lt;?php
namespace Craft;

class BusinessLogicCommand extends BaseCommand
{
public function actionResaveFODEntries()
{
    print("### Resaving entries for Fundamentals Of Digital\n(So search indexes are updated by causing PreParse to re-pull in the generated content).\n\n");

    $criteria = craft()-&gt;elements-&gt;getCriteria(ElementType::Entry);
    $criteria-&gt;section = 'fundamentalsOfDigital';


    foreach ($criteria as $entry)
    {
        $success = craft()-&gt;entries-&gt;saveEntry($entry);

        if (!$success)
        {
            print("Failed to save entry $entry-&gt;title\n");
        }        
        else
        {
            print("Saved $entry-&gt;title\n");
        }
    }
  }


}

To actually run the command I do this:

php yiic-env.php --env="console" businesslogic resaveFODEntries

...note the use of a specific environment, console in there - this is defined in my config/general.php with appropriate settings