Hydroformylation of 1,6-dienes with carbonylhydridotris(triphenylphosphine)rhodium

Abstract

Hydroformylation of a number of 1,6-dienes has been achieved at room temperature and atmospheric pressure using [Rh(H)CO(PPh₃)₃] as catalyst. Octa-1,6-dienes are hydroformylated specifically at the terminal double bond and good selectivity for the n-aldehyde is observed when a 2:1 mixture of hydrogen and carbon monoxide are used. Both mono- and di-formyl derivatives are formed from 4,4-diacetylhepta-1,6-diene, with a strong preference for n-aldehydes. The effect of catalyst concentration on product distribution is reported. Octa-1,3,7-triene can be selectively hydroformylated by protecting the diene moiety as its cycloadduct with sulphur monoxide or dioxide, and whilst methylenecyclopentane undergoes regiospecific hydroformylation, methylenecyclobutane is isomerised to methylcyclobutene.