The short answer is 'no'. It does the opposite. But you may be able to play the degradation to your advantage.
Image field 'flatness' with respect to focus
Lenses project an image onto a sensor. If you focus the lens at some target in the center of the frame (image center has the best focus the lens can offer) and compare this to the quality you get near the edges and corners of the frame, you'll notice there is a slight degradation of focus as you get farther from the center of frame. BTW, you can adjust focus until you find the corner is optimally focused, but then you'll notice the center is no longer optimally focused.
This happens because lenses do not have a "flat" plane of focus. It is slightly curved. Corrective elements are used to improve the flatness, but this just makes the lens "nearly" flat... not "perfectly" flat.
Image field 'flatness' with respect to optical aberrations
There are numerous optical aberrations depending on the optical train. Coma is common. There are other types of aberrations but it's not easy to generalize them.
These aberrations mean that if you had a point-source of light, it would no longer focus as a "point" ... it might be a larger "spot" instead of a point. But it will often change shape entirely... and become elongated or start to form other interesting shapes (tear-drop shapes, or bat-wing shapes, etc. these vary depending on the type and severity of the aberration and that will be based on the optical train.)
Effects of increasing the angle of view
A lens doesn't project a neat rectangular image... it projects a large spot into the camera body ... but much of the light falls outside the boundaries of the sensor.
The image degradation I mentioned above continue to degrade as you inspect areas of the image that are farther away from the image center (presuming you optimized focus for the center). This means those areas outside the boundaries of the sensor are even more degraded than the corners.
When you use a focal reducer (tele-compressor) to reduce the focal length, you increase the lenses true angle of view and parts of the image that would have been outside the frame will now appear as part of your image.
The typical effect is that you get a wider angle of view, but the edges and corners are suffer from even more degradation of focus and optical aberrations than were present without the tele-compressor.
That aside... sometimes the optical aberrations are taken as an artistic element in the image (for example a "swirled" bokeh effect). The lens wont be capable of delivering a tack sharp image from corner to corner ... but if you play the effect nicely, you might enjoy the images you can capture with it.