Amidophosphines, chiral

Use of ferrocenylmonophosphine (fU-(A)-PPFA 5a for the same reaction improved the enantioselectivity.24,25,26 Here, the hydrosilylation product was oxidized into ( y)-l-phenylethanol 3 with 52% ee (entry 3). The ferrocenylmonophosphine 6 supported on Merrifield polystyrene resin has been also used for the hydrosilylation of styrene, though the enantioselectivity was lower (15% ee) (entry 4).27 Several chiral (/ -/V-sulfonylaminoalkyl)phosphines 7 were prepared from (A)-valinol and used for the asymmetric hydrosilylation of styrene.28 For styrene, phosphine 7a which contains methanesulfonyl group was most effective giving (asymmetric hydrosilylation (entries 6-9).29,29a... 

The asymmetric hydrogenation of enol esters can also be catalyzed by chiral amidophosphine phosphinite catalysts derived from chiral amino acids, but the enantioselectivity of these reactions has thus far been only moderate.35... 

Lithiation of the dicarboxamide 365 is similarly diastereoselective, and after two successive n-BuLi-(—)-sparteine lithiations C2-symmetric products such as 367 can be made with high ee (Scheme 156) Attempted double lithiation of 365 in one pot fails with n-BuLi with s-BuLi-(—)-sparteine the major product is the meso isomer of 367 ". The amidophosphine 366 has been used as a chiral ligand for Pd chemistry the amides can be reduced to amino groups with BHsiTHF . 

When we entered the field, Tomioka et al. had just introduced the dialkylzinc addition to N-sulfonylimines in the presence of chiral amidophosphine-copper(II) complexes, producing high levels of enantioselectivity (up to 94% ee) [27]. At the... 

Leautey, M. Castelot-Deliencourt, G. Jubault, P. Pannecoucke, X. Quirion, J.-C. Synthesis of a-substituted /i-amidophosphines by diastereoselective alkylation. A new access to chiral ligands for asymmetric catalysis. 

Catalytic asymmetric reaction was realized by using 8 mol% of copper iodide and 32 mol% of the chiral amidophosphine 24 to afford the /(-substituted cycloalkanones... 

Owing to strategic reasons, Lonza exited the dextrometorphan business before the process could be transferred. Subsequently a further study of the hydrogenation of 10, using iridium complexes with chiral amidophosphine-phosphonite ligands, was published by another group [14]. An enantioselectivity of 86% ee was reached, but the chemoselectivity was low. 

Ortiz [47] recently described the ortho-directed lithiation of R,R-diphenylami-nophosphazenes 64 followed by electrophilic quenching as an efficient process for the preparation of / -chiral ort/io-functionahzed P-chirogenic amidophosphinates 65 in good yields and diastereoselectivities. The usefulness of the method was shown with the preparation under mild reaction conditions of a variety of functionalized P-chiral compounds 66 in high yield and excellent stereoselectivity, including phosphinic esters, amides, thioamides, phosphine oxides, and (2-aminophenyl)phosphine boranes (Scheme 21). 

Addition to Imines. CuOTf-catalyzed alkylation of N- acii-vated)imines also proceeds with dialkylzinc reagents. Use of a chiral amidophosphine leads to the asymmetric alkylation of N-(p-toluenesulfonyl)imines with dimethyl-, diethyl-, and di-E propylzinc in good yields and high enantioselectivities. CuOTf is the most active catalyst but efficiency is optimal with Cu(OTf)2 (eq 117). Chiral binaphthylthiophosphoramides give slightly lower selectivities. ... 

The highly electrophilic character of the SES imine imparts good reactivity towards many soft organometallic conqiounds. Organozincs were added to several SES imines in the presence of a catalytic amount of copper(II) triflate and an enantiopure amidophosphine to deliver chiral sulfonamides in very good yields and enantiomeric excesses (eq 20). ... 

---