Asymmetric Synthesis of ES-285, an Anticancer Agent Isolated from Marine Sources

The asymmetric synthesis of (2S,3R)-2-amino-3-octanedecanol hydrochloride (ES-285·HCl) was achieved in eight steps in ca. 38 % overall yield from the N-benzylimine-derived from (R)-2,3-O-isopropylidene glyceraldehyde, which is easily available on gram scale from the inexpensive precursor D-mannitol. Highly diastereoselective addition of methylmagnesium bromide to the N-benzylimine was the key step to create the vic-amino alcohol moiety with the appropriate configuration. Regioselective ring opening of an intermediate aminoepoxide enabled the introduction of the long hydrocarbon chain at C4.Financial support of the Spanish Ministry of Science and Innovation and European Regional Development Fund (CTQ2008-00187/BQU) and the Government of Aragón (GA E-71) is acknowledged.Peer reviewe

Synthetic Routes to Chiral Nonracemic and Racemic Dihydro- And Tetrahydrothiophenes

A study was conducted to demonstrate synthetic routes to chiral nonracemic and racemic dihydro- and tetrahydrothiophenes. The study presented a comprehensive survey of the methods available for the asymmetric synthesis of dihydro- and tetrahydrothiophene compounds with chirality at carbon. The synthetic routes to chiral nonracemic dihydro- and tetrahydrothiophenes were divided according to the way the asymmetry was introduced. The asymmetric synthesis of dihydro- and tetrahydrothiophenes represented an emerging area in organic synthesis. Chiral nonracemic dihydro- and tetrahydrothiophenes were obtained either from chiral auxiliaries and chiral synthons or by application of organocatalytic and desymmetrization processes. The use of chiral auxiliaries for the preparation of enantiomerically pure compounds had found wide applications for a variety of reactions