Electrophile-directed diastereoselective alkylation of prochiral enediolates

Prochiral substituted enediolates undergo diastereoselective alkylation with P-chiral primary iodohydrin derivatives, with selectivities up to 97:3. The most selective reactions occur with dienediolates, but reasonable selectivities can also be obtained with alkyl- and aryl-substituted enediolates. The presence of the lithioalkoxy substituent on the enolate is crucial for selectivity, as is the presence of the P-oxygen in the electrophile, leading to the proposition that alkylation occurs via a lithium-coordinated assembly of nucleophile and electrophile. The reaction also works with chiral secondary protected iodohydrins, leading to the efficient construction of contiguous quaternary and tertiary asymmetric centers.