A (fluor)ry of activity: The transfer of an intact trifluoromethyl group from a hypervalent iodine reagent to an aliphatic alcohol occurs smoothly upon activation by zinc bis(triflimide). This constitutes a straightforward method for the preparation of trifluoromethoxy alkyl derivatives, compounds otherwise difficult to access.

Schieb mal rüber: Der Transfer einer intakten Trifluormethylgruppe von einem hypervalenten Iodreagens zu einem aliphatischen Alkohol verläuft glatt bei einer Aktivierung durch Zinkbis(triflimid). Dies ist eine einfache Methode zur Synthese von Trifluormethoxyalkyl‐Derivaten, die sonst nur schwer zugänglich sind.

Chelated amino acid ester enolates are excellent nucleophiles for palladium-catalyzed allylic alkylations. These enolates react rapidly at -78 degrees C and in general without isomerization of pi-allyl palladium complexes. Therefore, they are good candidates for mechanistic studies and regioselective reactions. Terminal pi-allyl palladium complexes are preferentially attacked at the least hindered position giving rise to linear products, as illustrated with several (E)-configured allylic substrates. Under isomerization free conditions the branched products are formed preferentially from the corresponding (Z)-allyl substrates. An interesting behavior is observed in the reaction of secondary allylic substrates. Aryl-substituted substrates show a significant memory effect which can be explained by an asymmetric pi-allyl complex. For alkyl-substituted substrates a strong dependence of the regioselectivity on the leaving group is observed, which can be explained by different conformations in the ionization step. Under isomerization free conditions the product ratio gives important information about this step.

Rehabilitated: The rhodium‐catalyzed allylic alkylation is indeed a viable alternative to the better‐known palladium‐catalyzed version. Rhodium complexes show a different regioselectivity and have a low tendency for isomerization. The allylations proceed with excellent chirality transfer for both branched and linear products (see scheme; Tfa=trifluoroacetyl).

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