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A relatively unexploited commercial ligand, (R,R)-DUPHOSiPr (1b) was tested in the Pd 0 -catalysed asymmetric allylic alkyation reaction using rac-1,3-diphenylpropenyl acetate as substrate, malonate as nucleophile and a variety of Pd precatalysts under standard conditions. Excellent ee values (up to Ն 98 %) could be obtained with 1b, but the conversions were generally inferior to those obtained using (R,R)-Me-DUPHOS (1a) under similar conditions. It was also observed that there was a switch in the absolute configuration of the malonate product to (R) on using 1b to form the catalyst. This was an indication of the complementary nature of these two ligands. In order to explain this, a rigorous detailed semi-

It has come to our attention that the absolute configuration shown for (R,R)-DUPHOS-iPr (1b) shown in Figure 1 of the original article, [1] was in fact the (S,S) configuration and not the purported (R,R) absolute configuration. This is a consequence of the subtlety of the Cahn-Ingold-Prelog rules, a point that had previously been made by Burk et al., [2] but had unfortunately been overlooked by us at the time of writing and of submitting this paper. Thus, Fig This therefore means that, in fact, complexes 2b and 2c, have the opposite absolute configuration to that shown as Figure 2 in our original paper (see the corrected version for Figure 2 below), and since the calculations on the Fukui function were inadvertently performed on the complex with the opposite absolute configuration to that used in the experiments (see Figure 4 in our original paper for the picture of the calculated structure), the preferred site of attack (C1) on the π-allyl complex 2b (indicated as C1 in the corrected Figure 2) will give the malonate product with the (R) absolute configuration, as observed. Gratifyingly, this now explains on a very simple basis, the switch in the absolute configuration of the malonate product from (S) to (R) on going from (R,R)-DUPHOSMe to (R,R)-DUPHOS-iPr, and shows that, in both cases, it is the electronic effect and not any stereochemical effect, that is the controlling influence.[a]

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