Lewis acid catalyzed diastereoselective [3+4]-annulation of donor–acceptor cyclopropanes with anthranils: synthesis of tetrahydro-1-benzazepine derivatives
作者:Zhe-Hao Wang、Huan-Huan Zhang、Dao-Ming Wang、Peng-Fei Xu、Yong-Chun Luo
DOI:10.1039/c7cc04239f
日期:——
A Lewisacidcatalyzed [3+4]-annulation reaction between cyclopropane 1,1-diesters and anthranils has been developed. This annulation consists of a reaction sequence involving ring-opening/aromatization/nucleophilic addition. Thereinto, aromatization is the driving force for this annulation. Using this reaction, a series of 8-oxa-1-azabicyclo[3.2.1]octanes can be prepared conveniently with excellent
Multicomponent Synthesis of Pyrroles from Cyclopropanes: A One-Pot Palladium(0)-Catalyzed Dehydrocarbonylation/Dehydration
作者:William J. Humenny、Polydoros Kyriacou、Katarina Sapeta、Avedis Karadeolian、Michael A. Kerr
DOI:10.1002/anie.201206177
日期:2012.10.29
es yields tetrahydro‐1,2‐oxazines, which in turn undergo a Tsuji dehydrocarbonylation to give dihydro‐1,2‐oxazines (see scheme; dba=dibenzylideneacetone). Addition of base to this reaction mixture results in clean conversion to pyrroles. The result is a flexible three‐component strategy for the synthesis of tetrasubstituted pyrroles.
Copper(I)-Catalyzed Carbometalation of Nonfunctionalized Cyclopropenes Using Organozinc and Grignard Reagents
作者:Kohei Endo、Takeo Nakano、Yutaka Ukaji
DOI:10.1055/s-0034-1379959
日期:——
A highly efficient method was developed for the copper(I)-catalyzed carbometalation of various nonfunctionalized and functionalized cyclopropenes. Electrophilic trapping of the cyclopropylmetal intermediates gave multifunctionalized cyclopropanes.
Synthesis of five-membered cyclic nitrones based on the Lewis acid-catalysed [3+2]-annulation reaction of donor–acceptor cyclopropanes with 1,4,2-dioxazoles
作者:Zhe-Hao Wang、Huan-Huan Zhang、Peng-Fei Xu、Yong-Chun Luo
DOI:10.1039/c8cc04656e
日期:——
A novel synthesis of five-membered cyclic nitrones has been developed based on the Lewis acid-catalysed [3+2]-annulation reaction of D–A cyclopropanes with 1,4,2-dioxazoles. Broad substrate scope and generally good yield make this reaction useful in the preparation of nitrones. When a suitable 1,4,2-dioxazole was used, nitrone and tetrahydrofuran could be prepared in one pot with high atom economy
Isopropylidene diphenylsulfurane and isopropylidene triphenylphosphorane react by the same (Re) face of the alkylidene malonate derived from the acetonide of (d)-glyceraldehyde to produce almost exclusively a single diastereoisomer of the corresponding dimethyl cyclopropane-1,1-dicarboxylate.