Enantioselective palladium-catalyzed tandem

To address the need for a more general catal)Tic method of s)mthesizing allylic ammonium ylides for [2,3]-rearrangements that is amenable to enantioselective catalysis, our group recently developed a palladium-catalyzed tandem allylic amination/[2,3]-Stevens rearrangement of tertiary amines that proceeds through a palladium-n-allyl intermediate rScheme 15.34T Metal-catalyzed allylic aminations between primary or secondary amines... 

A tandem palladium-catalyzed reaction can effect a similar transformation to produce 2-vinyl-substituted heterocyclic systems as in Eq. 8E.11. By varying the amino acid moiety of the ligand, 83% ee could be obtained from the use of the glycine-derived ligand 129 [161]. A maximum enantioselectivity of 65% ee has been recorded for this type of reaction in an earlier study with BINAP as ligand [ 162]. Because both ( )- and (Z)-isomers gave the same enantioselectivity, attack on the rapidly interconverting 7t-allyl intermediates seems to determine the selectivity. Modest enantioselectivities have been reported for the related asymmetric preparation of 2-vinylpiperazine and 1,4-benzodioxane derivatives [163,164],... 

Examples of electrophilic addition of secondary phosphines to alkenes or alkynes were described. [114, 124, 125, 135]. Glueck [124-126] reported enantioselective tandem reaction of alkylated/arylation of primary phosphines catalyzed by platinum complex, proceeding with formation of chiral phosphaace-naphthenes. Palladium-catalyzed hydrophosphination of alkynes 219 tmder kinetic resolution conditions gave access to 1,1-disubstituted vinylphosphine boranes 220. However, despite screening several chiral ligands, temperatures, and solvents, the... 

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