Branched selective hydroformylation:  A useful tool for organic synthesis

Hydroformylation reactions that show branched regioselectivity are reviewed. The mechanism of hydroformylation and the current state of the art in linear selective hydroformylation is briefly discussed prior to a more in depth discussion on synthetically useful branched selective hydroformylation reactions. The review divides these into several different classes; hydroformylation of internal cyclic alkenes, acyclic internal alkenes, aryl alkenes, terminal alkenes bearing electron withdrawing groups, terminal alkenes bearing groups that can potentially co-ordinate to the rhodium catalysts, and simple terminal alkenes. Recent advances in asymmetric hydroformylation are also discussed. The review aims to provide the non-specialist and expert reader with the information required to assess the type of substrate, catalyst and reaction conditions that are likely to be conducive to obtaining branched aldehydes in a hydroformylation reaction.