16982-00-6Relevant articles and documents
New Cuparene-Derived Sesquiterpenes with Unprecedented Oxygenation Patterns from the Sea Hare Aplysia dactylomela
Ichiba, Toshio,Higa, Tatsuo
, p. 3364 - 3366 (1986)
Five new sesquiterpenes, cyclolaurene (2), cyclolaurenol (3), cyclolaurenol acetate (4), cupalaurenol (5), and cupalaurenol acetate (6), were isolated from the sea hare Aplysia dactylomela.Their structures including absolute configurations were deduced from spectroscopic data and chemical interconversion.The terpenes 3-6 are the first examples in which bromine and hydroxyl or acetoxy substituents are reversed in their positions from those usually found in related compounds, e.g., laurinterol (1).
Synthesis of cuparene and herbertene via a common intermediate
Ho, Tse-Lok,Chang, May-Hua
, p. 2479 - 2482 (1999)
A dihydroisobenzofuran (13) was obtained from β-ionone in 10 steps via an intramolecular Diels-Alder reaction. On further oxidation, reductive ring opening and decarboxylation, cuparene and'herbertene were synthesized.
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Daeniker,H.U. et al.
, p. 1 - 5 (1972)
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Use of aromatic radical-anions in the absence of THF. Tandem formation and cyclization of benzyllithiums derived from the attack of homo- and bishomoallyllithiums on α-methylstyrenes: Two-pot synthesis of cuparene
Cohen,Kreethadumrongdat,Liu,Kulkarni
, p. 3478 - 3483 (2001)
When a homo- or bishomoallyllithium, generated by reductive lithiation of the corresponding phenyl thioether by the radical anion lithium 1-(dimethylamino)naphthalenide (LDMAN), is added to α-methylstyrene, a tandem addition/cyclization to a phenyl-substituted five- or six-membered-ring occurs. The yields are compromised by polymerization of the α-methylstyrene, a process favored by tetrahydrofuran (THF), the solvent used to generate lithium aromatic radical anions. Thus, a new method of generating LDMAN (unsuccessful for other common radical anions) in the absence of THF has been developed. The radical anion can be generated and the reductive lithiation performed in dimethyl ether at -70 °C. After the addition of diethyl ether or other solvent, and evaporation of the dimethyl ether in vacuo, the α-methylstyrene is added and the solution is warmed to -30 °C. When the unsaturated alkyllithium is primary, no adduct forms in THF due to polymerization of the α-methylstyrene, but moderate yields are attained in a solvent containing mainly hexanes. It was also found that the cyclized organolithiums, which would have become protonated in the presence of THF, can be captured by an electrophile, even at ambient temperature. A two-pot synthesis, the most efficient reported, of the sesquiterpene (±)-cuparene in 46% yield, using this technology is reported.
Catalytic asymmetric total syntheses of (+)-α-cuparenone, (+)-cuparene and (+)-herbertene
Shaw, Kundan,Niyogi, Sovan,Nandi, Rhituparna,Bisai, Vishnumaya
, (2020)
A general catalytic asymmetric route to either enantiomers of sesquiterpenes, cuparenes (1–2) and herbertenes (8–9) is disclosed from commercially available 3-methyl cyclopenten-2-one. Following a catalytic enantioselective addition of arylboronic acids to enone 15, compounds 14a-b with all carbon quaternary stereocenters are synthesized in up to 90percent ee in the presence of Pd(II)-PyOx (pyridine oxazoline). Compounds 14a-b are used as precursors for the asymmetric total syntheses of (+)-cuparene (1a) (35percent overall yield in 3 steps), α-(+)-cuparenone (1b) (56percent overall yield in 2 steps), and (+)-herbertene (8a) (34percent overall yield in 3 steps).
New Strategy for Forging Contiguous Quaternary Carbon Centers via H 2 O 2 -Mediated Ring Contraction
Hu, Jiadong,Yu, Xin,Xie, Weiqing
, p. 2517 - 2524 (2017/09/28)
Stereospecific construction of contiguous quaternary carbon centers constitutes a major challenge in natural product synthesis. A general protocol that enables stereospecific construction of all stereoisomers of such a moiety remains elusive. In this article, we will discuss the oxidative ring contraction of all-substituted cyclic α-formyl ketones mediated by H 2 O 2, which provides a facile access to the stereospecific construction of contiguous quaternary carbon centers.
RCM-based approach to (±)-cuparene
Srikrishna,Satyanarayana,Prasad
, p. 1511 - 1516 (2008/02/03)
An efficient approach to the aromatic sesquiterpene cuparene has been described starting from the readily available β-ionone and employing a combination of epoxide rearrangement-based ring-contraction and ring-closing metathesis reactions as key steps. Copyright Taylor & Francis Group, LLC.
