I'm curious as to if you're interested? [closed]

"I'm curious as to if you're still interested [..]"

Is this valid grammar? I've also thought of 'curious in if you're still interested', neither now sound right and starting to question.

Absent-mindedly placed my phone in tea, the w key isn't working whatsoever, and wondering whether I would be able to use this, or what synonyms I could use in its place.

Solution 1:

To paraphrase Little Eva:

"I'm curious to see if you're interested"

Solution 2:

Grammatically speaking, the answer is no.

As far as I know, noun clauses led by if cannot serve as the object following a preposition. Therefore, neither "as to if..." nor "in if..." in your sentence is valid.
However, noun clauses led by if can serve as the direct object of a transitive verb, so it is ok to say

I'm curious to know if you're still interested.

where "if you're still interested" serves as the object of know.

Another possible alternative, from a grammatical perspective, is that you can replace if by whether in your original sentence, because noun clauses led by whether can be used almost the same as is an ordinary noun: it can serve as the subject, the noun predicate, or the object of both verbs and prepositions. So you can say

I'm curious as to whether you're still interested.

This alternative is grammatically correct and sounds acceptable to me, but may not be as good as the previous one.