Pd-catalyzed asymmetric allylic alkylation

Pd-catalyzed asymmetric allylic alkylation is a typical catalytic carbon-carbon bond forming reaction [ 126 -128]. The Pd-complex of the ligand (R)-3b bearing methyl, 2-biphenyl and cyclohexyl groups as the three substituents attached to the P-chirogenic phosphorus atom was found to be in situ an efficient catalyst in the asymmetric allylic alkylation of l-acetoxy-l,3-diphenylprop-2-en (4) with malonate derivatives in the presence of AT,0-bis(trimethylsilyl)acetamide (BSA) and potassium acetate, affording enantioselectivity up to 96% and quantitative... 

Scheme 30. Example of Pd-catalyzed asymmetric allylic alkylation...

Scheme 2. Pd-catalyzed asymmetric allylic alkylation of 7 is followed by a Pd-catalyzed intramolecular C-N bond formation and a Pd-catalyzed intramolecular Heck-type alkylation in Mori and Shibasaki s total synthesis of lycorane (1995).

Scheme 17. Trost s total synthesis of pancrastatin chiral ligand 102 is utilized in a Pd-catalyzed asymmetric allylic alkylation (1995).

Raluy E, Dieguez M, Pamies O (2007) Sugar-based diphosphoroamidite as a promising new class of ligands in Pd-catalyzed asymmetric allylic alkylation reactions. J Org Chem 72 2842-2850... 

The conversion of racemic butadiene monoepoxide to a single enantiomer of 54 (R=CH2OH) using Pd-catalyzed asymmetric allylic alkylation was uncovered by Trost [141]. By using a slightly modified ligand, the alkylation with phthalim-... 

Recently, Trost reported an efficient Pd-catalyzed asymmetric allylic alkylation of 1-tetralones [175] and a-arylketone 83 creating a quaternary center as exemplified by the synthesis of 84 (Scheme 7) [176]. Two a-heterocyclic ketones were also alkylated with similar results. Ferrocene-based ligands are effective in pro-... 

Trost, B.M. et ah. Synthesis of chiral chromans by the Pd-catalyzed asymmetric allylic alkylation (AAA) scope, mechanism, and applications, J. Am. Chem. Soc., 126, 11966, 2004. 

Alkylthio groups, except phenylthio and thiophene substituents, coordinate to palladium in the Pd-catalyzed asymmetric allylic alkylation, forming nine-membered chelates... 

A new chiral o-(phosphinoamino)phenyl sulfoxide has been demonstrated as an efficient ligand in the Pd-catalyzed asymmetric allylic alkylations of 1 with dimethyl sodiomalonate using [Pd(7r-allyl)Cl]2, affording (5)-2 [45% ee with (5)-36a].f ... 

The first attempt to use chiral /3-phosphino sulfoxides as chiral ligands was successfully accomplished in Pd-catalyzed asymmetric allylic alkylations and aminations.t ... 

Nemoto and Hamada [50] has described the development of a new class of chiral phosphorus ligand - aspartic acid-derived P-chirogenic diaminophosphine oxides, DIAPHOXs - and their application to several Pd-catalyzed asymmetric allylic substitution reactions. Pd-catalyzed asymmetric allylic alkylation was initially examined in detail using diaminophosphine oxides 77, resulting in the highly enantioselective construction of quaternary stereocenters. With the use of the Pd-DIAPHOX catalyst system, asymmetric allylic alkylation, asymmetric allylic amination, and enantioselective construction of quaternary carbons were achieved with high ee (up to 97-99% in many cases) (Scheme 24). 

In 2007, Chan and eo-workers reported the synthesis of a new class of chiral ferrocenyl heterobidentate P/S ligands, which are readily available from Ugi s amine, and they reported their applieation in Pd-catalyzed asymmetric allylic alkylation of l,3-diphenyl-2-propenyl acetate with indoles. The corresponding C3 alkylated indoles derivatives were produced in good yields with up to 96% ee (Scheme 6.78). 

Subsequently, chiral binaphthyl-based terminal alkene-phosphine hybrid ligands were synthesized and employed in the Pd-catalyzed asymmetric allylic alkylation of indoles with 168 to give the desired products in high yields (72-99%) with good to excellent enantioselectivity (75-94% ee) (Scheme 6.80). To evaluate the effect of the alkene group of (S)-167, a ligand... 

SCHEME 13.43. Pd-Catalyzed asymmetric allylic alkylation in the synthesis of carbovir. 

Kinetic resolution of 2,3-dihydro-2-substimted 4-quino-lones by Pd-catalyzed asymmetric allylic alkylation has... 

Chapsal BD, Ojima I. Total synthesis of enantiopure (+)-7-Lycorane using highly efficient Pd-catalyzed asymmetric allylic alkylation. Org. Lett. 2006 8(7) 1395-1398. 

Trost BM, Jiang C. Pd-Catalyzed asymmetric allylic alkylation. A short route to the cyclopentyl core of viridenomycin. Org. Lett. 2003 5(9) 1563-1565. 

Laurent R, Caminade AM, Majoral JP (2005) A third generation chiral phosphorus-containing dendrimer as ligand in Pd-catalyzed asymmetric allylic alkylation. Tetrahedron Lett 46 6503-6506... 

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