Sequential Platinum‐Catalyzed Cycloisomerization and Cope Rearrangement of Dienynes
作者:Sun Young Kim、Youjung Park、Young Keun Chung
DOI:10.1002/anie.200905361
日期:2010.1.8
Enyne‐enyne‐o: Tandem cycloisomerization of dienynescatalyzed by platinum dichloride and subsequent Coperearrangement affords bicyclic rings (see scheme; Z=NTs, O, CH2), such as bicyclo[3.2.2]nonadienes 1 or tetrahydrocyclohepta[c]pyrans and ‐pyridines 2, in high yields.
烯炔-烯炔:二氯化铂催化的二烯的串联环异构化和随后的Cope重排提供双环(见方案; Z = NTs,O,CH 2),例如双环[3.2.2]壬二烯1或四氢环庚基[ c ]吡喃和吡啶2,高产。
Anomalous Reactivity and Selectivity in the Intermolecular Diels–Alder Reactions of Multisubstituted Acyclic Dienes with Geometrical Isomers of Enals
A Lewis-acid catalyzed intermolecular Diels–Alderreaction between multisubstituted acyclic dienes and the E and Z isomers of α,β-enals was studied. It was found that the diene reacted selectively with the Z-isomer of the α,β-enal.
Chiral Gold Complex-Catalyzed Hetero-Diels–Alder Reaction of Diazenes: Highly Enantioselective and General for Dienes
作者:Bin Liu、Kang-Nan Li、Shi-Wei Luo、Jian-Zhou Huang、Huan Pang、Liu-Zhu Gong
DOI:10.1021/ja3110472
日期:2013.3.6
A chiral gold(I) complex-catalyzed highly regio- and enantioselective azo hetero-Diels-Alder reaction has been developed. The chiral gold(I) complex acting as a Lewis acid exhibits high efficiency in the activation of urea-based diazene dienophiles. Moreover, this chiral goldcatalyst also rendered a cascade intramolecular enyne cycloisomerization/asymmetric azo-HDA reaction.
Synthesis of (<i>E</i>
)-4-Methylhexa-3,5-dien-1-ol and Its Diels-Alder Reaction with Thioester Dienophiles: A Short Enantioselective Synthesis of Bicyclic Lactones
A one-step synthesis of (E)-4-methylhexa-3,5-dien-1-ol is presented in which a metal-counterion exchange promotes an oxy-anion-accelerated [1,3]-sigmatropic shift. The increased reactivity of thioesters as dienophiles and acylating agents allows the exclusive endo-Diels–Alder reaction with this dienyl alcohol and subsequent lactonisation. Use of chiral thioesters leads to enantiomerically enriched
Synthesis of 1,2- and 1,4-disubstituted tricarbonyl(pentadienyl)iron(+1) cations and reactions with heteroatom nucleophiles
作者:William A. Donaldson、Myung Jong Jin、Peter T. Bell
DOI:10.1021/om00028a035
日期:1993.4
Tricarbonyl(1,2-dimethylpentadienyl)iron(+1) (3a), tricarbonyl(2-methyl-1-phenylpentadienyl)iron(+1) (3b),tricarbonyl(1,4-dimethylpentadienyl)iron(+1) (4a),and tricarbonyl(4-methyl-1-phenylpentadienyl)iron(+1) (4b) were prepared as their hexafluorophosphate salts by the dehydration of the appropriately substituted dienol complexes. The reaction of each cation with methanol and with triphenylphosphine proceeds with excellent regioselectivity to afford the corresponding methyl ethers and phosphonium salts, respectively. The reduction of each cation with sodium cyanoborohydride was also examined. Only for cation 3b was good regioselectivity observed; the other cations gave mixtures of diene complexes.