Aldehydes and Ketones

in this video we're gonna go over reactions associated with ketones and aldehydes so let's begin with the reduction reaction of ketones and aldehydes so if you we have two ketone or an aldehyde with sodium borohydride followed by h3o plus what do you think is going to happen in this reaction at a b h4 can reduce a ketone or an aldehyde into an alcohol in this case you're gonna get a secondary alcohol now lithium aluminum hydride will have the same effect so let's say if we react an aldehyde with lithium aluminum hydride the end result will still be the same and that is the carbonyl group will be reduced to an alcohol now let's go over the mechanism of the first reaction so here we have a ketone and we're gonna be active with sodium borohydride so the sodium ion has a positive charge and boron has a negative formal charge because it's attached to four hydrogen atoms and hydrogen is more electronegative than boron so if you focus on the boron hydrogen bond boron has an electronegativity value of approximately 2.0 and for hydrogen is 2.1 so therefore hydrogen is slightly more electronegative than boron therefore it has a partial negative charge now the carbon atom of the carbonyl group contains a partial positive charge and so this hydride ion or this hydrogen with a negative partial charge is attracted to the carbonyl carbon so it attacks it and this is and so far we added eight hydrogen to the no carbon now in the second step we are going to react the alkoxide ion with h3o plus and so it's gonna pick up a hydrogen turn in into a secondary alcohol and so that is the mechanism for this reaction now let's go over some other reactions so here we have an ester and let's react it with lithium aluminum hydride sodium borohydride is not strong enough to reduce esters and carboxylic acids but lithium aluminum hydride can reduce them all so go ahead and predict the major product for that reaction as