Issues with CP2102 USB bus-powered and esp8266
At the very least, you nead a different 3.3V source. If it tries transmitting anything, just the ESP8266 will draw over 100 mA, which is the maximum the LDO in CP2102N can provide.
Also, you cannot just short two voltage sources and call it a day - you need to protect those outputs against reverse current. CP2102N is fine, since it handles both directions on VDD, but you probably need a series diode on the output of that boost converter.
Lastly, I'm not entirely sure that boost will work like you intend - it probably won't work with input voltage higher than output.