Bis(triarylphosphite) ligands 1 - 4 were prepared in optically pure forms from (R)- or (S)-binaphthol and (ArO)2PCl, and their Rh(I) complexes have been used as catalysts for hydroformylation of vinyl acetate. The corresponding branched aldehyde, 2-acetoxypropanal, was given in up to 95% regioselectivity and in 49% ee.