Synthesis of (+)‐Varitriol Analogues via Novel and Versatile Building Blocks Based on Julia Olefination

Abstract

The synthesis of (+)‐varitriol (1) analogues was achieved through the use of Julia olefination. The potential anticancer properties of 1 coupled with our interest in developing building blocks that enable olefin formation under the Julia protocol constitute the basis of our research project. Efforts are aimed at the synthesis of building blocks 2 and 3 and to explore their use towards the synthesis of (+)‐varitriol analogues. Herein, we would like to present the synthesis of building block 3 and its ability to react with variety of substituted aromatic‐, heterocyclic‐ and carbohydrate‐derived aldehydes to yield alkene 6 in moderate to good yields with E as the major isomer. The successful coupling of 2 with(furanoside moieties) aldehydes 5k, 5m and 5n in particular and the obtainment of compound 23 reflect the promise associated with the new strategy.

Convenient Access to Acyl‐Substituted Bis(styrylbenzenes) Based on Building Blocks Using Julia Olefination and Weinreb Amide Chemistry

“…[14] Here again, the E/Z mixture of olefination products from the Julia olefination reaction were isomerized to the E isomer by using a catalytic amount of iodine and heating to reflux in toluene. [14] Here again, the E/Z mixture of olefination products from the Julia olefination reaction were isomerized to the E isomer by using a catalytic amount of iodine and heating to reflux in toluene.…”

“…Stilbene aldehydes 30-36 were then subjected to a modified Julia olefination reaction with the second building block 10. [14] Here again, the E/Z mixture of olefination products from the Julia olefination reaction were isomerized to the E isomer by using a catalytic amount of iodine and heating to reflux in toluene. All of the obtained unsymmetrical (E,E)-bis(styrylbenzenes) 37-43 with the WA functionality were new compounds (see Table 2).…”

Is their potential for post-synthetic brominating reactions on benzene bridged PMOs?

“…The whole mixture was refluxed during 6 h. The brownish powder was filtrated and washed with tetrachloromethane, until it turned white again. [33,34] A three-necked round bottom flask was loaded with 0.25 g benzene bridged PMO material and 50 mL of tetrachloromethane. The mixture was brought to reflux before adding 1 g of N-bromosuccinimide (NBS, Acros, 99%) and a spatula point of azobisisobutyronitrile (AIBN, Sigma-Aldrich, 98%).…”

Applications of Mitsunobu Reaction in total synthesis of natural products

“…The total synthesis 77 was subsequently reported by Taylor et al [143] They applied Horner-Wadsworth-Emmons (HWE) and Ramberg Backlund reactions in their strategy. However, several other protocols were reported for the synthesis of natural [144,145] and its synthetic analogues [146,147] from varitriol. However the total synthesis of 77 completed with reaction between sulfone 81 and 82 in the presence of lithium hexamethyl disilazane in THF as solvent.…”