Synthesis of novel 5-alkyl/aryl/heteroaryl substituted diethyl 3,4-dihydro-2H-pyrrole-4,4-dicarboxylates by aziridine ring expansion of 2-[(aziridin-1-yl)-1-alkyl/aryl/heteroaryl-methylene]malonic acid diethyl esters

• Satish S. More,
• T. Krishna Mohan,
• Y. Sateesh Kumar,
• U. K. Syam Kumar and
• Navin B. Patel

Beilstein J. Org. Chem. 2011, 7, 831–838, doi:10.3762/bjoc.7.95

• -[(aziridin-1-yl)-1-alkyl/aryl/heteroaryl-methylene]malonic acid diethyl esters in very good to excellent yields under mild reaction conditions. The electronic and steric impact of the substituents on the kinetics of ring expansion of N-vinyl aziridines to pyrrolines has been studied. Various diversely

• -vinyl substituted aziridines; ring expansion; sodium iodide; Introduction Vinylaziridines are a particularly interesting class of aziridine derivatives that lend themselves to a host of highly useful synthetic transformations [1]. They are versatile electrophiles and notably undergo regioselective ring

• chemistry and new applications of these compounds are being continuously explored [10][11][12][13][14][15][16][17][18][19][20][21][22]. However, not much attention has been paid to N-vinyl substituted aziridines. Thus, N-vinyl substituted aziridines provide an opportunity for researchers to explore their

Synthetic applications of gold-catalyzed ring expansions

• David Garayalde and
• Cristina Nevado

Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87

• gold-catalyzed ring expansion of 1-oxiranyl-1-alkynylcyclopropanes [43][44]. An alternative method for obtaining disubstituted pyrroles via gold-catalyzed ring expansion was reported by Davies and co-workers who employed alkynyl aziridines 51 as intramolecular nucleophiles [45]. Ring expansion from the

• aziridines onto the adjacent alkyne afforded the 2,5-disubstituted pyrroles 52 in high yields (Scheme 16). In 2011, Barluenga et al. developed a new methodology for the preparation of 1,6-disubstituted regioisomeric cyclohexadienes 54 and 54' (Scheme 17) [46]. The process resulted in a five-to-six-membered

• aziridines. Gold-catalyzed synthesis of disubstituted cyclohexadienes. Gold-catalyzed synthesis of indenes. Gold-catalyzed [n + m] annulation processes. Gold-catalyzed generation of 1,4-dipoles. Gold-catalyzed synthesis of repraesentin F. Gold-catalyzed ring expansion of cyclopropyl 1,6-enynes. Gold

α,β-Aziridinylphosphonates by lithium amide-induced phosphonyl migration from nitrogen to carbon in terminal aziridines

• David. M. Hodgson and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2010, 6, 978–983, doi:10.3762/bjoc.6.110

• David. M. Hodgson Zhaoqing Xu Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK, Fax: +44(1865) 285002 10.3762/bjoc.6.110 Abstract N-Phosphonate terminal aziridines undergo lithium 2,2,6,6-tetramethylpiperidide-induced N- to C-[1,2

• acids; aziridines; lithiation; migration; synthetic methods; Introduction The synthesis of aminophosphonic acids and their derivatives has attracted considerable attention, since the presence of such functionality, typically as amino acid surrogates, leads to interesting bioactivity in, for example

• our investigations [9][10][11][12][13] on the generation and subsequent chemistry of α-lithiated terminal aziridines [14], we considered whether α,β-aziridinylphosphonates 3 could be accessed by α-lithiation of N-phosphonate terminal aziridines 1, followed by N- to C-[1,2]-anionic phosphonyl group

Palladium- catalyzed cross coupling reactions of 4-bromo- 6H-1,2-oxazines

• Reinhold Zimmer,
• Elmar Schmidt,
• Michal Andrä,
• Marcel-Antoine Duhs,
• Igor Linder and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2009, 5, No. 44, doi:10.3762/bjoc.5.44

• alcohols [20], aziridines [21], pyrrolizidines [22], and pyrrolidine derivatives [15][23][24]. In the context of our ongoing exploration of the synthetic potential of these heterocycles we were interested to modify the substitution pattern of the C-4,C-5 double bond of 6H-1,2-oxazines [25][26][27]. Herein

The enantiospecific synthesis of (+)-monomorine I using a 5-endo- trig cyclisation strategy

• Malcolm B. Berry,
• Donald Craig,
• Philip S. Jones and
• Gareth J. Rowlands

Beilstein J. Org. Chem. 2007, 3, No. 39, doi:10.1186/1860-5397-3-39

• mode of cyclisation. [1][2][3][4][5][6] The methodology allows the conversion of epoxides (X = O) or aziridines (X = N-PG) (2) into the desired trisubstituted tetrahydrofurans or pyrrolidines (5) via a series of sulfone-mediated transformations (Scheme 1). Ring-opening 2 with the sulfone-stabilised

Pd-catalysed [3 + 3] annelations in the stereoselective synthesis of indolizidines

• Olivier Y. Provoost,
• Andrew J. Hazelwood and
• Joseph P. A. Harrity

Beilstein J. Org. Chem. 2007, 3, No. 8, doi:10.1186/1860-5397-3-8

• + 3] annelation of aziridines and Trost's conjunctive allylsilane reagent. We have also found that reduction of the lactam unit of 11 and acetylation of the hydroxyl group takes place smoothly to provide 13, demonstrating the potential of these intermediates for the synthesis of slaframine and related