(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• , Chiara and co-workers have described a novel complementary approach in which the oxazoline ring is generated by SN2 nucleophilic displacement reaction from the β-hydroxyurea 30 via the triflate intermediate 31 (Scheme 3) [65]. A similar methodology was used by the same authors to prepare the trehazolin

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• between the methoxy ether and the olefin were probably responsible for this unexpected outcome. However, introduction of a carboethoxy group on the terminus of the olefin 129 restored the regioselectivity observed by Kozikowski to give oxazoline 130. 5.2. Reinhoudt. Rearrangement of 1-(1-pyrrolidinyl)-1,3

• tributyltin fluoride [112]. After protecting group manipulations and formation of the diazoester 138 with p-nitrobenzenesulfonylazide (PNBSA), the key carbene insertion was achieved using copper(I) in the presence of bis-oxazoline 139. A 9:1 ratio of 141 and 142 was obtained after direct chloranil oxidation

Asymmetric synthesis of biaryl atropisomers by dynamic resolution on condensation of biaryl aldehydes with (−)-ephedrine or a proline- derived diamine

• Ann Bracegirdle,
• Jonathan Clayden and
• Lai Wah Lai

Beilstein J. Org. Chem. 2008, 4, No. 47, doi:10.3762/bjoc.4.47

• . A family of starting aldehydes 6a–f was made by the method of Meyers [36]. 2,3-Dimethoxybenzoic acid (1) was converted via its acyl chloride to oxazoline 3, from which the 2-methoxy group was displaced with a series of aryl Grignard reagents 4, yielding biaryloxazolines 5a–f (Scheme 1 and Table 1

• ). Removal of the oxazoline by methylation, reduction and hydrolysis returned the aldehydes 6a–f. Screening for selectivity by NMR In order to investigate the ratios of diastereoisomers formed as these aldehydes condensed with the resolving agents, 6a was mixed with 1 equiv of either 7 or 8 in toluene-d8 or

DBFOX- Ph/metal complexes: Evaluation as catalysts for enantioselective fluorination of 3-(2-arylacetyl)-2-thiazolidinones

• Takehisa Ishimaru,
• Norio Shibata,
• Dhande Sudhakar Reddy,
• Takao Horikawa,
• Shuichi Nakamura and
• Takeshi Toru

Beilstein J. Org. Chem. 2008, 4, No. 16, doi:10.3762/bjoc.4.16

• availability of commonly used classes of ligands for asymmetric catalysis, such as, TADDOLs [37][39][41][47], BINAPs [38][40][43][44][46][49][51][53][55][56][57] and bis(oxazoline) [33][34][36][42][45]. Of particular importance are BINAP ligands. Sodeoka et al. have used the latter ligands in asymmetric

• enantioselectivities [57]. This study is useful because, up until now, the fluorinated products obtained by Sodeoka's method have been prepared by diastereoselective methods [65][66][67]. Independently, our group has focused on the development of enantioselective fluorination and related reactions using bis(oxazoline

• ) ligands, Box-Ph [(S,S)-2,2'-isopropylidene-bis(4-phenyl-2-oxazoline)] and DBFOX-Ph [(R,R)-4,6-dibenzofurandiyl-2,2'-bis(4-phenyloxazoline)] [33][34][36]. As an extension of this study, we herein evaluate our DBFOX-Ph/metal catalysis for the enantioselective fluorination of 3-(2-arylacetyl)-2

A superior P-H phosphonite: Asymmetric allylic substitutions with fenchol- based palladium catalysts

• Bernd Goldfuss,
• Thomas Löschmann,
• Tina Kop-Weiershausen,
• Jörg Neudörfl and
• Frank Rominger

Beilstein J. Org. Chem. 2006, 2, No. 7, doi:10.1186/1860-5397-2-7

• product by employing electron withdrawing substituents on the P-donor atoms in P, N-oxazoline ligands[5] (Scheme 2) [6]. Such phosphites were thought to favor a more SN1-like addition at the substituted, allylic C-atom. High regio- and enantioselectivities were also achieved with biphenylphosphites by