The first catalytic enantioselective synthesis of oxaziridines is presented. The oxidation of aryl and alkyl aldimines with m-CPBA under organocatalytic conditions using cinchona alkaloid-derived catalysts furnished optically active oxaziridines in good yields and high enantioselectivities (up to 94% ee). Mechanistic investigations indicate a stepwise enantioselective oxidation process.
generation of amines by palladium-catalyzed nucleophilic benzylic addition of 2-methyl-substituted azaarenes to N-sulfonyl aldimines under neutral conditions via C-H bondactivation has been developed. This reaction represents a very efficient methodology for the synthesis of heterocycle-containing amines and thus opens a new way to access amines through C-H bondactivation.
Iron-Catalyzed Direct Alkenylation of 2-Substituted Azaarenes with <i>N</i>-Sulfonyl Aldimines via C–H Bond Activation
作者:Bo Qian、Pan Xie、Yinjun Xie、Hanmin Huang
DOI:10.1021/ol200684b
日期:2011.5.20
A novel iron-catalyzed alkenylation of 2-substituted azaarenes through sp3 C–Hbondactivation has been developed. A favorable E2-elimination is proposed as a key step to cleavage of C–H and C–N bonds for the construction of a C═C bond in high stereoselectivity. This transformation represents an efficient way to synthesize 2-alkenylated azaarenes from simple starting materials.
Divergent Selectivity in MgI<sub>2</sub>-Mediated Ring Expansions of Methylenecyclopropyl Amides and Imides
作者:Mark Lautens、Wooseok Han
DOI:10.1021/ja011110o
日期:2002.6.1
the reaction site in the dienolate with aryl aldimines and aldehydes as well as the size of the ring. Excellent divergent selectivity to five- vs. six-membered heterocycles is observed: alpha-alkylation/5-exo-tet cyclization (Z = NPh(2)) vs. gamma-alkylation/6-exo-trig cyclization (Z = 2-oxazolidone). Analogously, the reaction of the MCP imide with alkyl aldimines demonstrates the same selectivity by
Use of a sterically demanding Lewis acid to direct ring expansion of monoactivated methylenecyclopropanes
作者:Catherine Taillier、Yann Bethuel、Mark Lautens
DOI:10.1016/j.tet.2007.05.081
日期:2007.8
A novel syntheticroute for the preparation of functionalized alkylidene pyrrolidines via a MAD/n-Bu4NI-mediated ringexpansion of monoactivated MCP was developed. The substrate scope for this reaction was found to be broad for a variety of aldimines and symmetrically as well as unsymmetrically monoactivated MCPs yielding the corresponding five-membered heterocyclic compounds in good yields (up to
开发了一种通过MAD / n - Bu 4 NI介导的单活化MCP扩环制备官能化亚烷基吡咯烷的新颖合成途径。发现该反应的底物范围对于多种醛亚胺而言是宽泛的,并且对称地以及非对称地单活化的MCP以良好的产率(高达92%)产生相应的五元杂环化合物。该方法是对以前有关MCP环扩环的报告的补充,该报告显示,只需改变催化剂体系,就可以从同一MCP中实现不同杂环骨架的选择性合成。
An N-Linked Bidentate Phosphoramidite Ligand (N-Me-BIPAM) for Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to N-Sulfonylarylaldimines
A chiral N-linked C2-symmetric bidentate phosphoramidite (N-Me-BIPAM) was newly developed for the rhodium-catalyzed enantioselective addition of arylboronicacids to N-sulfonylimines. This ligand achieved high enantioselectivities in a range of 84–99% ee in additions of arylboronicacids to N-tosyl- and N-nosylarylaldimines.