[blaisem]

Sorry to interrupt, but thanks to everyone involved for this great (and for me, informative) discussion

[Babcock_Hall]

Making the phenyl ester and reducing it to the aldehyde seems reasonable on paper.

[willug]

Does anyone know any better reagents for doing this (acid to aldehyde)? Seems like one of those big unsolved problems.

I wonder how you might think about designing such a reagent...

[discodermolide]

Not unsolved.
The Rosenmund reduction of acid chlorides by hydrogenation in the presence of Pd(barium sulphate or other de-activated catalyst.

[willug]

Is that typically more selective than DIBAL? It's still two steps from a carboxylic acid though... so perhaps no better than reduction/oxidation.

[discodermolide]

Unless you have conflicting functional groups it is extremely selective you do not get over-reduction.
And the two steps are a lot easier to do than those involving the manipulation of organometallic reagents and oxidising agents.