Divinylcarbinols 17 and 18, CS-symmetrical and cisconfigured, were desymmetrized by Sharpless' asymmetric epoxidation. This furnished anti-configured monoepoxy alcohols 19 (85% ee) and 20 (94% ee), respectively, or their mirror images (ent-19, 84% ee; ent-20, 95% ee). 20 (ent-20) was reduced by Red-Al ® regio-and chemoselectively, providing syn-1,3-diols ent-21 (21) at low and ent-22 (22) at higher temperature (94-95% ee). They should allow the obtention of more elaborated syn-1,3-diols.The asymmetric desymmetrization of prochiral molecules with or without stereocenters (i. e., meso compounds) is an efficient means for generating multifunctional compounds enantioselectively, 1,2 one advantage being that, in principle, the underlying substrates can emerge from highly efficient 'bidirectional synthetic strategies '. 3 In this context the asymmetric desymmetrization of divinylcarbinol and derivatives thereof by Sharpless' asymmetric epoxidation 4 (SAE) received considerable attention. This process was examined with divinylcarbinol (1), 5 with its methallyl analog 2, 5c,6 and with trans-configured dialkenylcarbinols 3 7 (Scheme 1). Several of the resulting epoxy alcohols 4-6 were obtained with exceptionally high ee values: up to 99%. This was explained by Schreiber et al. 5c based upon formal kinetics; the crucial point being that in these cases the initial asymmetric epoxidation is followed by an ee-enhancing kinetic resolution through a second epoxidation.Epoxy alcohols 4 and 5 (Scheme 1) were employed as enantiomerically pure building blocks in the synthesis of polyhydroxylated natural products such as sugars or polyol macrolide antibiotics, 5,6 while type-6 epoxy alcohols have not seen many synthetic applications yet. They are amenable, though, to the stereocontrolled synthesis of anti-configured 1,3-diols through a regioselective ringopening of the epoxide ring by a hydride nucleophile as shown by Hatakeyama et al. 7b-d : epoxy alcohols 6 and Red-Al ® give 1,3-diols 7 (Scheme 2, top).The latter compounds exhibit the anti-1,3-diol motif 8. It abounds in polyol, polyene macrolide antibiotics, a class of compounds well beyond 200 members. 8a There, however, motif 8 is always intermingled with the diastereomorphic motif 11 exhibiting the syn-configuration. Considering this and the persistent need for methods tailored for the synthesis of such macrolides 8 we investigated the reaction sequence outlined in Scheme 2 below Hatakeyama's work. It is stereochemically complementary to his method and starts from a cis-configured type-12 divinylcarbinol. Enantio-and diastereoselective desymmetrizations by SAE were meant to furnish type-9 epoxy alcohols and their reductions to lead to syn-1,3-diols 10. These diols are versatile examples of type-11 diols.Scheme 2 Divinylcarbinol → epoxy alcohol → 1,3-diol strategies. R 3 R R OH OH R 1 OH OH R 3 R OH OH R 1 OH OH R OH R R O OH R R 8 7 11 10 9 12 6 SAE Hatakeyama´s work: This work: Scheme 1 Previous desymmetrizations of divinylcarbinols by Sharpless' asymmetric epoxidation. a)...