Binaphthyl phosphoric add

At almost the same time. You and coworkers developed the same type of asymmetric reaction by employing the binaphthyl phosphoric add Ig. In their case, the isopropyl ester group was the best substituent as for the enantioselectivity [25], This type of asymmetric reduction became the topic of much interest and many excellent methods for the construction of chiral amine substructures were developed. Various pharmacologically important substractures, such as a-amino esters and tetrahydroquinolines, could be obtained with excellent enantioselectivities. 

The binaphthyl phosphoric add 69 (1 mol%) was used in the a-hydroxylation of cychc 1,3-dicarbonyl compounds of type 33 with 4-chloronitrosobenzene (43b), affording the corresponding a-hydroxy P-ketoesters in high OIN selectivity (94 6), good yields and enantioselectivities (46-88%, 68-98% ee). Several ester derivatives such as methyl, ethyl, isopropyl or tm-butyl were well tolerated [100], with the present protocol being extended to the related P-diketones. 

N-Boc-protected ethyl trifluoropyruvate imine was effectively used in a F-C reaction with indole derivatives for synthesizing, in high selectivities, quaternary a-amino acids via catalysis with chiral phosphoric acid 26e [64]. A binaphthyl-based chiral sulfonimide [42c] and a chiral squaramide-based hydrogen bond donor [42a] were used as effective catalysts for promoting F-C reaction of indoles with imines. Recently, the F-C alkylation of arenes with glyoxylate imine was described via a chiral phosphoric add (Scheme 35.11) [34]. 

In 2009, List introduced a binaphthyl-derived, chiral disuUbnimide (28) as a new structural motif of a powerful chiral Bronsted add that could activate simple aldehydes [80, 81]. Evaluation of the catalytic activity and stereocontrolling ability of 28 in the Mukaiyama aldol reaction of silyl ketene acetal with naphthaldehyde revealed that 28 was not only far more reactive than phosphoric acid 29 and phos-phoramide 30 but also capable of affording the aldol product with high enantiose-lectivity (Scheme 7.53). 

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