Allyl carbonates deracemization

Proper choice of leaving group and nucleophile can produce deracemization of allylic carbonates. When an allylic carbonate is treated with Pd2(dba)3 and (21), the loss... 

Reactions with Oxygen Nucleophiles. The hist report of the reaction of oxygen nucleophiles was for the deracemization of cyclic allylic ethers, for example, the palladium(0)-catalyzed reaction of 2-cyclohexeny 1-1 -methyl carbonate with sodium pivalate afforded the pivalate ester in 94% yield and 92% ee. This reaction was extended to other cyclic allylic carbonates. 

The resulting derivatives were applied with success in the standard asymmetric allylic alkylation (up to 97 % ee) [134, 136] or in transformations involving either specific allylic substrates (2-cycloalkenyl derivatives, up to >99% ee) [135, 137], unsymmetrical substrates (monosubstituted allyl acetate, up to 83% ee) [140], or especial nucleophiles (nitroalkanes [141], iminoesters [138 a], or diketones [139, 140, 142]). Such ligands were also effective in the formation of quaternary chiral carbon through allylic substitution (eq. (6)) [138, 143], deracemiza-tion of vinyl epoxides (up to 99% ee) [144], or alkylation of ketone enolates [138 b], and deracemization of allylic derivatives [145]. 

Deracemization of cyclic allyl esters has been achieved under the standard conditions generally described by Trost et al. using the sodium salt of pivalate, as distinct from dialkylmalonates as nucleophile (eq A9)P This reaction has been exemplified with a large number of 3-(acyloxy)cycloalkenes, and with carbon and nitrogen nucleophiles. ... 

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