Synthesis of cis-C-Iodo-N-Tosyl-Aziridines using Diiodomethyllithium: Reaction Optimization, Product Scope and Stability, and a Protocol for Selection of Stationary Phase for Chromatography
摘要:
The preparation of C-iodo-N-Ts-aziridines with excellent cis-diastereoselectivity has been achieved in high yields by the addition of diiodomethyllithium to N-tosylimines and N-tosylimine-HSO(2)Tol adducts. This addition-cyclization protocol successfully provided a wide range of cis-iodoaziridines, including the first examples of alkyl-substituted iodoaziridines, with the reaction tolerating both aryl imines and alkyl imines. An ortho-chlorophenyl imine afforded a beta-amino gem-diiodide under the optimized reaction conditions due to a postulated coordinated intermediate preventing cyclization. An effective protocol to assess the stability of the sensitive iodoaziridine functional group to chromatography was also developed. As a result of the judicious choice of stationary phase, the iodoaziridines could be purified by column chromatography; the use of deactivated basic alumina (activity IV) afforded high yield and purity. Rearrangements of electron rich aryl-iodoaziridines have been promoted, selectively affording either novel alpha-iodo-N-Ts-imines or alpha-iodo-aldehydes in high yield.
1,2-Aryl and 1,2-Hydride Migration in Transition Metal Complex Catalyzed Diazo Decomposition: A Novel Approach to α-Aryl-β-enamino Esters
作者:Nan Jiang、Zhaohui Qu、Jianbo Wang
DOI:10.1021/ol016324p
日期:2001.9.1
esters in good yields and high stereoselectivity. The effect of the catalysts on the migratory aptitude of 1,2-aryl over 1,2-hydride migration was studied. A reaction mechanism involving a "bridged" phenoniumion is proposed. Reaction: see text.
New Approaches to Polysubstituted Pyrroles and γ-Lactams Based on Nucleophilic Addition of Ti(IV) Enolates Derived from α-Diazo-β-keto Carbonyl Compounds to <i>N</i>-Tosylimines
作者:Changqing Dong、Guisheng Deng、Jianbo Wang
DOI:10.1021/jo0605039
日期:2006.7.1
The Ti(IV) enolates derivedfrom α-diazo-β-keto esters or ketones efficiently add to TiCl4-activated N-tosylimines to give δ-N-tosylamino substituted α-diazo-β-keto carbonyl compounds. The diazo decomposition of the addition products occurs under Rh2(OAc)4-catalyzed or photoinduced conditions to afford pyrrole or γ-lactam derivatives, both in high yields.
showed good inhibitory activity against fungal strains whereas other derivatives had mild or diminished activity in comparison with standard drug clotrimazole. The antimicrobial study indicated that compounds having electron-withdrawing groups showed the highest activity. Interestingly, these tested compounds showed weak antiviral activity against Vaccinia virus, Human Coronavirus (229E), Reovirus-1
A rhodium complex coordinated with a chiral diene, (R,R)-2,5-diphenylbicyclo[2.2.2]octa-2,5-diene (Ph-bod), catalyzed the asymmetric addition of dimethylzinc to N-tosylarylimines to give high yields of chiral 1-aryl-1-ethylamines with high enantioselectivity (94-98% ee).
Chiral Copper Complexes of Phosphino Sulfenyl Ferrocenes as Efficient Catalysts for Enantioselective Formal Aza Diels−Alder Reactions of <i>N</i>-Sulfonyl Imines
作者:Olga García Mancheño、Ramón Gómez Arrayás、Juan C. Carretero
DOI:10.1021/ja038494y
日期:2004.1.1
catalytic amount of silver perchlorate, copper(I) bromide complexes of planar chiral 1-phosphino-2-sulfenylferrocenes behave as very efficient chiral Lewis acids catalysts in the formal Aza Diels-Alder reaction of N-arylsulfonyl aldimines with electron-rich dienes (Danishefsky's and related dienes). Mixing of equimolar amounts of the readily available enantiopure ferrocenyl P,S-bidentate ligand and CuBr quantitatively