[harini_5]

I have an unsaturated aldehyde. I want to reduce the carbon-carbon double bond without disturbing the aldehyde group. Is there any specific reagent for this?

[kiwi]

although its a little "flavour of the month", a number of methods exist for reducing a,b-unsaturated aldehydes organocatalytically. eg. see http://www.rsc.org/publishing/journals/OB/article.asp?doi=b711499k (Org. Biomol. Chem., 2007, 5, 3407 - 3417)

[harini_5]

Can lithium aluminium hydride be used for this purpose?

[zq]

No. Try NaBH(OAc)₃.

[pngeneric]

No. Try NaBH(OAc)₃.

[Custos]

What about catalytic hydrogenation -- Pd on carbon catalyst and one equivalent of hydrogen. That should go for the double bond rather than the aldehyde.

[DaveD]

another possibility is a diimide reduction.  I believe this is selective for olefin over carbonyl reduction.

[reflux]

If all else fails, I've seen some pretty efficient 3-step Luche reduction / hydrogenation / oxidation sequences although it doesn't look pretty on paper.  Good luck.

[kiwi]

If all else fails, I've seen some pretty efficient 3-step Luche reduction / hydrogenation / oxidation sequences although it doesn't look pretty on paper.  Good luck.

if quick and ugly is on the cards, you could modify this idea by reducing everything at once with LAH, then oxidising back up.

[HP]

Its also possible first to protect the CHO group by reaction with acetic anhydride to the corresponding CH(OCOCH3)2 and the do hydrogenation of = bond with some of the known hydrogenation paths. The last step will be deprotection of CHO group. May be much simple protection procedure is the acetal formation with ethylene glycol or some other CHO protecting group.

[movies]

Copper hydride conjugate reduction should also work for this purpose, but Pd/C + H₂ is easier!

Also, I don't think that NaBH(OAc)₃ does conjugate reductions.  It will, however, usually reduce aldehydes to alcohols.

[romzulu]

protection followed by non polar reduction should work here. aldehyde need reducing agent acts on dipolar carbony vs alkene need not polar.

[Markov]

if quick and ugly is on the cards, you could modify this idea by reducing everything at once with LAH, then oxidising back up.

This is not school-book true. LAH would normally go selectively on the carbonyl. (1,2-addition). Go for hydrogenation, dude.  If that reduces the aldehyde and the olefin, oxidise the alcohol back up using your favourite alcohol-to-aldehyde oxidation method.
e.g swern, TPAP/NMO, IBX, or maybe TEMPO/bleach.