128231-56-1Relevant academic research and scientific papers
Intramolecular acylation of α-sulfinyl carbanions with masked α,β-unsaturated esters: a general strategy to 5-alkylidene-2-cyclopentenones
Pohmakotr, Manat,Thamapipol, Sirinporn,Tuchinda, Patoomratana,Reutrakul, Vichai
, p. 1806 - 1820 (2007)
A general method for the preparation of 5-alkylidene-2-cyclopentenones and their 2-phenylsulfanyl substituted derivatives, involving the intramolecular acylation of α-sulfinyl carbanions with cyclopentadiene-α,β-unsaturated esters as the key reaction followed by flash vacuum pyrolysis, is described. The reactions start from readily available Diels-Alder adducts, synthons of α-carbanions of α,β-unsaturated esters.
Double Activation Catalysis for α′-Alkylidene Cyclic Enones with Chiral Amines and Thiols
Wang, Zhou-Xiang,Zhou, Zhi,Xiao, Wei,Ouyang, Qin,Du, Wei,Chen, Ying-Chun
supporting information, p. 10678 - 10682 (2017/08/09)
Cooperative catalysis has contributed greatly to the progress of asymmetric synthesis. However, double-activation catalysis has been less explored, especially for covalently tethered species. Here, we present a double-activation strategy for α′-alkylidene cyclic enone substrates that uses a chiral primary amine and 2-mercaptobenzoic acid to promote regio- and chemoselective addition to generate the complex interrupted iminium ion species. Significantly enhanced reactivity and enantioselectivity were observed for β-regioselective Michael addition and Friedel–Crafts alkylation with malononitriles and indoles, respectively, which produced a spectrum of chiral cyclic adducts with an exo-alkylidene group. Moreover, a HRMS study detected a few key covalently tethered intermediates among the substrates and catalysts, which helped elucidate the catalytic mechanism.
Silver(I)-catalyzed ring-contractive rearrangement: A new entry to 5-alkylidene-2-cyclopentenones
Zhao, Liang,Wang, Jinlian,Zheng, Hongyan,Li, Yun,Yang, Ke,Cheng, Bin,Jin, Xiaojie,Yao, Xiaojun,Zhai, Hongbin
, p. 6378 - 6381 (2015/01/09)
A novel silver(I)-catalyzed ring-contractive rearrangement of 5-substituted 6-diazo-2-cyclohexenones has been developed, providing a new and efficient access to 5-alkylidene-2-cyclopentenones. The AgOTf-catalyzed reaction proceeds through metal-carbenoid formation followed by endocyclic allyl [1,2] migration with excellent stereoselectivity and broad substrate scope.
Pauson-khand reaction of allenic hydrocarbons: Synthesis of 4-alkylidenecyclopentenones
Antras, Frederic,Laurent, Stephane,Ahmar, Mohammed,Chermette, Henry,Cazes, Bernard
experimental part, p. 3312 - 3336 (2010/09/04)
The carbonyldicobalt-mediated alkyne/allene/CO cocyclization gives 4-alkylidenecyclopentenones as the major [2+2+1] cycloadducts. The regio- and stereoselectivities depend mainly on the substitution pattern of both the alkyne and the allenic moieties, whi
UTILIZATION OF PPh3-Ti(IV) REAGENTS. AN EFFICIENT α'-ALKYLIDENATION OF CYCLIC ENONES
Takanami, Toshikatsu,Suda, Kohji,Ohmori, Hidenobu
, p. 677 - 680 (2007/10/02)
PPh3-Ti(IV) reagents can promote regioselective condensation of cyclic enones with aldehydes to give α'-alkylidenecycloenones in good yields.
