38301-73-4Relevant academic research and scientific papers
Synthesis of derivatives of podocarpane-type diterpenoids through Diels-Alder cycloaddition and photo-decarbonylation from unmasked ortho-benzoquinone
Zhu, Guili,Liu, Bo
, p. 4070 - 4075 (2017)
Derivatives of podocarpane-type diterpenoids, including cassane-type, abietane-type and totarane-type diterpenoids, are either widely distributed natural products or common intermediates in synthetic and medicinal chemistry. Although unmasked ortho-benzoquinone has been used in [4+2] cycloadditions in sparse cases due to its multiple reactivity as diene, dienophile, heterodiene and heterodienophile, applications of this motif in cycloadditions of complex molecules are very rare. We report herein that this [4+2] process can be successfully extended to various polycyclic substrates, followed by a photo-decarbonylation, to generate versatile derivatives of podocarpane-type diterpenoids. Racemic synthesis of isolophanthins A & B and abietatrien-3β-ol was accomplished on the basis of this methodology.
Straightforward synthesis of aromatic polycyclic terpenoids through biomimetic cascade cyclizations triggered by photochemical electron transfer
Rosales, Viale,Zambrano, Jorge,Demuth, Martin
, p. 1798 - 1802 (2004)
Photoinduced biomimetic cascade cyclizations of suitably functionalized terpenoid arylpolyalkenes via radical cationic intermediates represent a powerful route to polycyclic compounds in a single operational step. In all cases examined, the radical cation, created selectively and exclusively at the ω-polyalkene position, is trapped in anti-Markovnikov fashion by water, liberating a free radical site, which ultimately initiates cascade-style bond formation to afford the all-chair polycyclic conformation containing one aromatic moiety. The products, some of which are podocarpic-type structures 17-19, are beneficially 3β-hydroxylated. Mechanistically, the reaction is probably initiated by a radical cation trapped by water prior to the cyclization event, which is driven by a pure radical-type process. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Tetraphenylphosphonium Tetrafluoroborate/1,1,1,3,3,3-Hexafluoroisopropanol (Ph4PBF4/HFIP) Effecting Epoxide-Initiated Cation-Olefin Polycyclizations
Tian, Yan,Xu, Xin,Zhang, Lin,Qu, Jin
supporting information, p. 268 - 271 (2016/02/03)
The use of an excess amount of tetraphenylphosphonium tetrafluoroborate in 1,1,1,3,3,3-hexafluoroisopropanol, which can stabilize the intermediate cation in the reaction, efficiently promoted epoxide-initiated cation-olefin polycyclization reactions with broad functional group tolerance and water and oxygen tolerance.
An unexpected (3 → 2)-hydride shift in phyllocladane (=13β-kaurane) diterpenoids and in related trimethyl-substituted Bi- and tricyclic compounds
Mueller, Ralph,Rueedi, Peter
, p. 439 - 456 (2007/10/03)
The conversion of 2α,3α-dioxy-substituted phyllocladane derivatives into the corresponding 3-ketone proceeds in an unexpected manner: Depending on the reaction conditions, the corresponding 3β-hydroxy-substituted compound is formed almost quantitatively,
An expeditious stereoselective total synthesis of (±)-podocarpa-2,8,11,13-tetraene and 3-oxygenated (±)-podocarpa-8,11,13-trienes by acid-catalyzed cyclialkylation route
Ghosh,Ghosh,Ghatak
, p. 553 - 565 (2007/10/02)
An expeditious total synthesis of (±)-podocarpa-2,8,11,13-tetraene (4) and the epimeric (±)-3-hydroxypodocarpa-8,11,13-trienes 5 and 6 by a stereoselective cyclialkylation route is described.
