Provided herein are 3,3-disubstituted 19-nor-steroidal compounds according to Formula (I):where R1, R2, R3, R3', R4, R6a, R6a, R11a, and R11b are as defined herein. Compounds of the present invention are contemplated useful for the prevention and treatment of a variety of CNS-related conditions, for example, treatment of sleep disorders, mood disorders, insomnia, anxiety, depression, traumatic brain injury (TBI), stress, and epilepsy.