Asymmetric Linear-Selective Hydroformylation of 1,1-Dialkyl Olefins Assisted by a Steric-Auxiliary Strategy.

Asymmetric hydroformylation of 1,2-dialkyl olefins was reported. In order to increase the enantiomeric induction, steric auxiliary sulfonyl groups were introduced. Using a Rh/Yanphos complex as catalyst, chiral aldehydes were obtained with high enantioselectivities under mild pressure. The easily removable auxiliary made this method a powerful tool in the preparation of important enantiopure building blocks.