| Christopher J. Cobley1, Kelli Gardner2, Jerzy Klosin2, Celine Praquin1, Catherine Hill1, Gregory T. Whiteker2, Antonio Zanotti-Gerosa1, Jeffrey Petersen3, and Khalil A Abboud4. (1) Dowpharma, Chirotech Technology Limited, The Dow Chemical Company, 321 Cambridge Science Park, Cambridge, CB4 0WG, United Kingdom, (2) Chemical Sciences, The Dow Chemical Company, 3200 Kanawha Turnpike, S. Charleston, WV 25303, (3) Department of Chemistry, West Virginia University, Morgantown, WV 26506, (4) Department of Chemistry, University of Florida, Gainesville, FL 32611 |
A series of mono and bidentate phosphites were prepared with (S-5,5’-6,6’-tetramethyl-3,3’-di-t-butyl-1,1’-biphenyl [(S-BIPHEN)] as a chiral unit and screened in asymmetric hydroformylation of allyl cyanide. Chiraphite and Binaphos ligands were synthesized and screened for comparison. Diphosphite 1 with 2,2’-diphenyl bridge was found to be the best ligand for asymmetric hydroformylation reaction of allyl cyanide with ee’s up to 80 % and regioselectivities (branch to linear ratio) of 20 with turnover frequency of 625 [h-1] at 35 oC. Binaphos gave enantioselectivities up to 77 %ee when the reaction was conducted in either acetone or neat, but with poor regioselectivity (b/l=2.8) and activity 7 times lower than that of 1.  |