Sordarin, an antifungal agent with a unique mode of action

• Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

• , treatment of substrate 94 with TBSCl in the presence of imidazole and a catalytic amount of DMAP provided 99. The Nagata reagent [49] readily transformed 99 into 100, presumably by 1,4-addition of cyanide ion and ensuing elimination of methanol. Unexpectedly, enone 100 was immune to the one-pot enol

Part 1. Reduction of S-alkyl- thionocarbonates and related compounds in the presence of trialkylboranes/air

• Jean Boivin and
• Van Tai Nguyen

Beilstein J. Org. Chem. 2007, 3, No. 45, doi:10.1186/1860-5397-3-45

• . Alternatively, radical C might fragment to conjugated enone E and stabilised TolSO2• radical. Neither compounds D nor enones E were ever isolated in the present work. Similarly, these compounds were not seen in a precedent work in which a "fast" hydrogen atom donor (hypophosphorus acid) or a "slow" hydrogen

Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy

• Asunción Barbero,
• Francisco J. Pulido and
• M. Carmen Sañudo

Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16

• result from the addition of the two organometallic species present in the solution (silylcuprate and R1Li). When R1Li is an alkenyllithium this reaction opens new alternatives for preparation of 7-membered rings by intramolecular Michael addition of the allylsilane group to the enone (Scheme 10

• structures ranging from three to seven membered rings, through processes which imply addition of the intermediate silylcuprate to an electrophile (enone, epoxide, nitrile, imine, etc) followed by Lewis-acid catalysed intramolecular cyclization, where the electrophile used determines the type of process and

One-pot synthesis of novel 1H-pyrimido[4,5-c][1,2]diazepines and pyrazolo[3,4-d]pyrimidines

• Dipak Prajapati,
• Partha P. Baruah,
• Baikuntha J. Gogoi and
• Jagir S. Sandhu

Beilstein J. Org. Chem. 2006, 2, No. 5, doi:10.1186/1860-5397-2-5

• with the addition of enone 2a to a clear solution. After completion and usual work-up, the product 3a was obtained in 85% yield. The reaction did not indicate the formation of any six-membered ring product pyrimido [4,5-c]pyridazine 5 as expected via [4+2] cycloadditions, which would have occurred

• synthetic scope this reaction, we reacted 1,3-dimethyl-6-hydrazinouracil 1 with an α-ketoalkyne (3-hexyn-2-one) in refluxing ethanol, the reaction proceeded somewhat differently from that with an enone (Scheme 2), as the intermediate could undergo a 5-exo-trig cyclisation in preference to 7-exo-trig. Here

A convenient synthesis of γ-functionalized cyclopentenones

• Nour Lahmar,
• Taïcir Ben Ayed,
• Moncef Bellassoued and
• Hassen Amri

Beilstein J. Org. Chem. 2005, 1, No. 11, doi:10.1186/1860-5397-1-11

• chromatography on silica gel (EtOAc/hexane). 4-Benzyl-3-methylcyclopent-2-enone (4d) Purified by column chromatography (hexane/AcOEt, 8/2). 1H NMR (300 MHz, CDCl3) δ 2.09 (s, 3H), 2.26–2.59 (m, 2H), 2.71 (m, 1H), 3.21 (m, 2H), 5.92 (s, 1H), 7.17–7.28 (m, 5H); 13C NMR (75 MHz, CDCl3) δ 19.4, 37.0, 39.0, 48.0

Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives

• Andrew Kennedy,
• Adam Nelson and
• Alexis Perry

Beilstein J. Org. Chem. 2005, 1, No. 2, doi:10.1186/1860-5397-1-2

• (Scheme 2).[24][25][26][27][28][29][30][31][32] Two-directional[33] oxidative ring expansion of 1,3-difuryl 1,3-amino alcohol derivatives 4 would yield a densely functionalised bis-enone which would be ripe for further functionalisation. The term "two-directional synthesis" is usually used to describe the