Synthesis of ¦Â-hydroxy-¦Ä-trichloromethyl-¦Ä-valerolactones by intramolecular samarium/ytterbium diiodide-mediated Reformatsky reaction

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• 作者：Thies M. Schulze ; Jö ; rg Grunenberg ; Stefan Schulz ; ^{stefan.schulz@tu-bs.de}
• 关键词：RBSYLLLDANNAQC-NTSWFWBYSA-N ; RBSYLLLDANNAQC-WDSKDSINSA-N ; YPDMRHGGPHOQTM-SECBINFHSA-N ; KUJAGEUCVYIEIN-SNVBAGLBSA-N ; JRUYCEHHQOARNW-OWOJBTEDSA-N ; VRJNZQCGHPMPNO-UHFFFAOYSA-N ; VRJNZQCGHPMPNO-VAYJURFESA-N ; OQTKJMJTNJYFGW-NZHGOTCASA-J ; VRJNZQCGHPMPNO-UOWFLXDJ
• 刊名：Tetrahedron Letters
• 出版年：2013
• 出版时间：20 February, 2013
• 年：2013
• 卷：54
• 期：8
• 页码：921-924
• 全文大小：761 K

文摘

The synthesis of ¦Á-methyl-¦Â-hydroxy-¦Ä-trichloromethyl-¦Ä-valerolactone was achieved by an intramolecular Reformatsky reaction. The cyclisation was effected by samarium diiodide or (for the first time) ytterbium diiodide. The diastereoselectivity of the reaction corresponds to earlier investigations by Molander. Consecutive stereoselective reactions during the esterification to the Reformatsky precursor 1,1,1-trichloropent-4-en-2-yl 2-bromopropanoate and in the Reformatsky reaction itself led to (3RS,4RS,6SR)-4-hydroxy-3-methyl-6-(trichloromethyl)tetrahydro-2H-pyran-2-one (3a) as the major formed diastereomer. The influence of the orientation of the substituents in the transition state is discussed.