# Can protection group be used in a Wolff–Kishner reaction?

How can I modify the ozonolysis of cyclohexene such that one of the aldehyde groups of the product, adipaldehyde, is efficiently protected as a base stable protecting group? I know that attempting to monofunctionalize adipaldehyde will lead to mixtures.

My aim is to then do a Wolff–Kishner reduction on the monoprotected dialdehyde.

• Are you trying to make hexanal from cyclohexene? – Zhe Jul 17 '18 at 14:48

I'm assuming you've carried out ozonolysis followed by mild reduction (e.g. using $\ce{Me2S}$) to generate a dialdehyde and now want to convert it to a monoaldehyde. Wolff-Kishner requires basic conditions, so you need a PG insensitive to base. Using ethylene glycol (1 equiv.) in mild acid over a dehydrating agent to generate an acetal would do, but you would need to optimise the conditions to ensure that only one of the aldehyde groups reacts. Then you can carry out Wolff-Kishner as usual and, finally, release the aldehyde in mild acid and excess water.