Sulfur containing quaternary carbon center

How to build a S-containing quaternary carbon center
like this:



ways I can find out:
1. enolate attack a S-nucleophile. ex. MeSSMe.
2. 3,3-sigmatropic rearrangement.
3. thioketone attacked by a Nu-.
4. thiol 1,4-addition.
5. thionium ions (ex. from thiolketal) attacked by a Nucleophile.
6. methoxyphenylthiomethyllithium addition to ketone, then rearrange using SOCl2 in py or MeSO2Cl /TEA.