Here’s the issue: if one is truly repentant, he would want to go to the sacrament of confession. So rejection of the sacrament likewise means an absence of complete sorrow for the sin. It’s taking God’s mercy for granted rather than using the means that Christ Himself gave us for forgiveness. We can’t be in a state of Grace if we are at the same time rejecting Christ’s gift to us, which is the Sacrament.
At the same time, not only do we need forgiveness of God, but we also need to be reconciled to the Church (and in many ways, those 2 are the same as the Church is the Body of Christ). That’s why we have to be absolved in the Sacrament.
Forgiveness reconciles us to God. Absolution reconciles us to the Church. The Sacrament of Confession/Reconciliation is the only way that we receive both (the two sides of the one coin).
So, the bottom line is: No, after a mortal sin, we cannot receive Communion until we have been to confession and been forgiven & absolved through the ministry of the priest.