765959-02-2Relevant academic research and scientific papers
Avoiding the classical resolution during the synthesis of MeO-BIPHEP and 3,3′-disubstituted derivatives
Gorobets, Evgueni,Wheatley, Bronwen M. M.,Hopkins, J. Matthew,McDonald, Robert,Keay, Brian A.
, p. 3843 - 3846 (2007/10/03)
The Ullmann coupling of 1 (R = H) gives a 2:1 mixture of diastereomers 2 (R = H) in 81% yield that are easily separated by silica gel chromatography. This procedure avoids the generally cumbersome and sometimes difficult resolution step with DBTA. Similar Ullmann couplings and separation of the corresponding diastereomers are employed with other derivatives of 1 (R = OtBu, iPr, Ph, and mesityl) ultimately affording a new series of 3,3′-disubsituted-MeO-BIPHEP derivatives. The use of these new derivatives in palladium-catalyzed asymmetric Heck reaction, Pd-catalyzed polyene cyclizations and rhodium-catalyzed hydrogenations is also reported.
Synthesis of ortho-phenyl substituted MeO-BIPHEP ligand and its application in Rh-catalyzed asymmetric hydrogenation
Wu, Shulin,He, Minsheng,Zhang, Xumu
, p. 2177 - 2180 (2007/10/03)
A new BIPHEP-type ligand with phenyl groups at the 3,3′-positions, o-Ph-MeO-BIPHEP 3 was prepared. This ligand afforded excellent enantioselectivities when used in the Rh-catalyzed asymmetric hydrogenation of α-dehydroamino acid derivatives. The strong influence of o-phenyl groups of the ligand on the enantioselectivities of the reaction has been demonstrated by a comparison with its parent ligand MeO-BIPHEP.
