Permethylpentalene Chemistry
Permethylpentalene Chemistry
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全甲基戊二烯化学
DOI：
10.1002/ejoc.200700033
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发表时间：
2007
影响因子：
2.8
通讯作者：
Ashley A
中科院分区：
文献类型：
--
作者：
Ashley A
通过双环[3.3.0]辛烷环体系的新型外围烷基化，设计了一种用于有机金属化学的过甲基戊二烯（Pn*）配体前体的合理液相合成方法。四甲基3,7 -二羟基二环-[3.3.0]八甲基- 2,6 -二烯- 2,4,6,8 -四羧酸盐(1)的四甲基化形成立体阻碍2，表现出流动性。脱羧，然后用br2afford4进行容易的双脱氢。最后两个甲基的亲核加成需要使用有机铈试剂，加成后得到六甲基化羟基氟烯5。采用非质子条件（LiCl/DMSO）脱水得到四烯六，四烯六是Pn*.6的外环异构体，包含双环乙烯-富勒烯单元，避免了8π反芳香结构。3号和4号都已进行了结构表征。（©Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007）
A rational solution‐phase synthesis of a permethylpentalene (Pn*) ligand precursor for use in organometallic chemistry has been devised through the novel peripheral alkylation of the bicyclo[3.3.0]octane ring system. Tetramethylation of tetramethyl 3,7‐dihydroxybicyclo[3.3.0]octa‐2,6‐diene‐2,4,6,8‐tetracarboxylate (1) forms sterically encumbered2which exhibits fluxionality. Decarboxylation to3followed by facile double dehydrogenation using Br2affords4. Nucleophilic addition of the final two methyl groups necessitates the use of an organocerium reagent and work‐up yields the hexamethylated hydroxy‐fulvene5. Dehydration is achieved using aprotic conditions (LiCl/DMSO) to afford the tetraene6, an exocyclic isomer of Pn*.6incorporates a bicyclic vinyl‐fulvene unit, avoiding an 8π anti‐aromatic structure. Both3and4have been structurally characterised.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)