1-(4-Alkyloxybenzyl)-3-methyl-1H-imidazol-3-ium organic backbone: A versatile smectogenic moiety

• William Dobbs,
• Laurent Douce and
• Benoît Heinrich

Beilstein J. Org. Chem. 2009, 5, No. 62, doi:10.3762/bjoc.5.62

• the cations and anions the physico-chemical properties of ionic liquids can be tuned and specifically optimised for a wide range of applications [5][6][7][8][9][10][11]. Although many organic cations (e.g. phosphonium, ammonium, pyridinium, imidazolium) can be used for the design of ionic liquids

An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens

• Kirsti Parikka and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2009, 5, No. 22, doi:10.3762/bjoc.5.22

• water solubility more generally, aryl modified phosphonium salts, carrying a –COOH group [38] or PEG attachments [39], have been developed but require extensive synthetic work. Previously, non-stabilized alkylphosphonium salts have appeared much less amenable than the benzyl analogues. A single paper

• MW catalyzed synthesis route where 3,5-dimethoxy benzaldehyde and unstabilized alkyltriphenyl phosphonium ylids react in DMSO/H2O works as well and alkylresorcinol precursors that do not have a commercially available alkanal starting material can be synthesized rapidly and efficiently by way of this

Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry

• Jiří Kulhánek,
• Filip Bureš and
• Miroslav Ludwig

Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11

• and 4-bromobenzyl(triphenyl)phosphonium bromide [37] by the Wittig reaction [37][38] in 37 and 54% yields, respectively. In contrast to the Horner–Wadsworth–Emmons reaction, this procedure afforded both (E)- and (Z)-stilbenes that were isomerized by heating with traces of iodine in toluene to afford

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• -ascorbic acid was elongated by two carbons to give ester 50 using a four-step sequence, the protected diol of which was then treated with H5IO6 to give the chiral aldehyde 51. On the other hand, 49 was converted to phosphonium salt 52, which was treated with aldehyde 51, and the resulting alkene was

• trilobacin (169) (ED50 <10−15 µg/mL) was over 1 billion times more potent against HT-29 than adriamycin (ED50 = 6.69 × 10−3 µg/mL) [71][72]. In 1996, Sinha’s group [73] reported the first total synthesis of 169 (Scheme 24). The phosphonium salt 172 and aldehyde 175 were prepared using the AD reaction from

• both the linear and the convergent strategies, synthetic efficiency and diversity. The phosphonium salt 279, which was synthesized from 274, was reacted with aldehyde 280 in a Wittig reaction, which, after global deprotection, allowed completion of the total synthesis of asimicin (260). The spectral

Synthesis of 2,6-trans- disubstituted 5,6-dihydropyrans from (Z)-1,5-syn-endiols

• Eric M. Flamme and
• William R. Roush

Beilstein J. Org. Chem. 2005, 1, No. 7, doi:10.1186/1860-5397-1-7

• /1860-5397-1-7 Abstract Certain (Z)-1,5-syn-diols 2 may be converted into 2,6-trans-5,6-dihydropyrans by using phosphonium salt 4 or phosphorane 5 as dehydrating agents. A more general four step procedure converts the (Z)-1,5-syn-endiols into enantiomeric dihydropyrans ent-3 via regioselective

• . In order to avoid the presence of nucleophilic counter ions, we turned to the use of phosphonium salt 4 and phosphorane 5 as the cyclodehydration reagents (Scheme 2).[24][25] Treatment of diol 2a with 4 in acetonitrile (0.05 M) at 0°C and warming slowly to 23°C provided a 9 : 1 mixture of trans and

• cyclodehydration of 2b with phosphorane 5 in toluene at 80°C proceeded with ca. 9 : 1 regioselectivity (entry 4), and use of the phosphonium salt 4 at -35°C also gave reasonably good results (84% e.e.). However, all attempts to dehdyrate the α,α'-oxygenated diol 7 with either 4 or 5 were unsuccessful. Given that