(R,R)-(+)-1,2-Bis(t-butylmethylphosphino)benzene (R,R)-BenzP*

• CAS: 919778-41-9
• Catalog Number: ACM919778419
• Category: Main Products
• Molecular Weight: 282.34
• Molecular Formula: C16H28P2
• Melting Point: 125 - 126 °C
• Appearance: Crystalline

Case Study

High-Performance Asymmetric Hydrogenation Using (R,R)-1,2-Bis(t-butylmethylphosphino)benzene as a Superior Chiral Ligand

Tamura, Ken, et al. Organic Letters 12.19 (2010): 4400-4403.

1,2-Bis(t-butylmethylphosphino)benzene (BenzP*) is a P-stereogenic bisphosphine ligand with a well-defined chiral environment and steric bulk designed for highly efficient asymmetric catalysis. This study demonstrated its exceptional performance in rhodium-catalyzed asymmetric hydrogenation reactions, delivering outstanding enantioselectivity and catalytic turnover across a broad range of functionalized alkene substrates.
Synthesis of BenzP* and its Rh Complex.
BenzP* was synthesized via a streamlined, stereosynthetic route and employed as a ligand in rhodium-catalyzed hydrogenation. BenzP* was prepared from (S)-tert-butylmethylphosphine-borane and o-dibromobenzene with complete stereochemical retention. A one-pot, four-step sequence-without intermediate isolation or chromatography-afforded crystalline (R,R)-BenzP* in 38% overall yield.
The ligand readily formed a well-defined rhodium complex ([Rh(cod)2]SbF6), characterized by X-ray crystallography, confirming effective steric shielding of the metal center.
Catalytic Performance
Rh complexes of (R,R)-BenzP* give high enantioselectivities up to 99.9% and high catalytic activity up to 10 000 h-1 in the asymmetric hydrogenation of a wide range of functionalized olefins. Excellent results were obtained with α-dehydroamino acids, aryl-enamides, and functionalized olefins, including challenging Z-isomers. High enantioselectivity was maintained even at catalyst loading as low as 0.01 mol% (S/C = 10,000).