A diastereoselective synthesis of α-tocopherol 1 (93% de) was achieved via two key steps, (i) a highly diastereoselective Shi epoxidation of a trisubstituted alkene and (ii) an acid supported, “anti-Baldwin” epoxide ring opening under inversion of configuration leading to the 6-membered chromanol ring.

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Vitamins U 0900Diastereoselective Synthesis of α-Tocopherol: A New Concept for the Formation of Chromanols. -An alternative synthesis of α-tocopherol (V) includes 2 key steps: the first is a highly diastereoselective Shi epoxidation of alkene (II) and the second an "anti-Baldwin" epoxide ring opening under inversion of configuration. -(CHAPELAT, J.; BUSS, A.; CHOUGNET, A.; WOGGON*, W.-D.; Org. Lett. 10 (2008) 22, 5123-5126; Dep. Chem., Univ. Basel, CH-4056 Basel, Switz.; Eng.) -Bartels 15-205