192123-92-5Relevant academic research and scientific papers
Synthesis of Polycyclic Frameworks through Iron-Catalyzed Intramolecular [5+2] Cycloaddition
Liu, Yongjiang,Zhang, Yanhui,Wang, Xiao,Fu, Shaomin,Liu, Bo
, p. 1978 - 1982 (2018)
A concise and efficient approach to the core of the C 18 /C 19 diterpenoid alkaloids and phomopsterone B is reported. Both syntheses share the same iron-catalyzed intramolecular [5+2] cycloaddition to assemble the tricyclo[6.3.1.0 1,6] ]dodecane skeleton. The following approach to the 6/5/6/7 tetracyclic core scaffold of C 18 /C 19 diterpenoid alkaloids features a regioselective Grignard addition/thermal Claisen rearrangement/RCM cyclization. Meanwhile the synthetic steps to access the spiro 6/5/6 tricyclic subunits of phomopsterone B were characterized as intramolecular aldol reaction, Wacker oxidation, and Criegee reaction.
Iron-Catalyzed Intramolecular Perezone-Type [5 + 2] Cycloaddition: Access to Tricyclo[6.3.1.01,6]dodecane
Liu, Yongjiang,Wang, Xiao,Chen, Song,Fu, Shaomin,Liu, Bo
supporting information, p. 2934 - 2938 (2018/05/28)
An iron-catalyzed perezone-type [5 + 2] cycloaddition toward tricyclo[6.3.1.01,6]dodecane scaffolds is presented, furnishing cycloadducts with two new C-C bonds and three to four stereogenic centers generated with typically good yields and excellent diastereoselectivities. Two independent conditions, catalytic FeCl3/PhCO3tBu (0.5 equiv/1 equiv) and stoichiometric FeCl3(2 equiv), have been respectively manifested to be applicable for various substrates. Mechanistically, the reaction may proceed via iron-mediated generation of a carbon cationic center, which triggers subsequent [5 + 2] cyclization. Derivation of the cycloadduct was conducted to testify the applicability of this method.
Intramolecular cationic [5 + 2] cycloaddition reactions promoted by trimethylsilyl triflate in 3.0 M lithium perchlorate-ethyl acetate: Application to a formal total synthesis of (±)-isocomene
Grieco, Paul A.,Walker, John K.
, p. 8975 - 8996 (2007/10/03)
Trimethylsilyl triflate is an effective reagent in 3.0 M lithium perchlorate-ethyl acetate for promoting intramolecular cationic [5 + 2] cycloaddition reactions. A formal total synthesis of the angular triquinane isocomene (10) is detailed. Cationic [5 + 2] cycloaddition of quinone monoketal 40 gives rise to tricyclic diketone 35 which is subsequently converted into the known tricyclic ketone 33. Addition of methyl lithium followed by acid-catalyzed rearrangement employing the Pirrung protocol affords (±)-isocomene (10).
