1 Introduction

Carbonyls: Aldehydes and Ketones . Carbonyls are compounds with a C=O bond. They can be either aldehydes or ketones If the C=O is on the end of the chain with an H attached it is an aldehyde. The name will end in –al CH3CHO ethanal CH3COCH3 If the C=O is in the middle of the chain it is a ketone The name will end in -one propanone Solubility in water The smaller carbonyls are soluble in water because they can form hydrogen bonds with water. C CH3 CH3 O H O H Pure carbonyls cannot hydrogen bond, but bond instead by permanent dipole bonding. Reactions of carbonyls In comparison to the C=C bond in alkenes, the C=O is stronger and does not undergo addition reactions easily. The C=O bond is polarised because O is more electronegative than carbon. The positive carbon atom attracts nucleophiles. This is in contrast to the electrophiles that are attracted to the C=C . nucleophile