Elimination of beta-thioalkoxy alcohols under Mitsunobu conditions. A new synthesis of conjugated enynes from propargylic dithioacetals

Micromixing enables chemoselective reactions of difunctional electrophiles with functional aryllithiums

Generation of highly unstable functional aryllithiums followed by chemoselective reactions with difunctional electrophiles were successfully achieved using flow microreactor systems equipped with micromixers to give highly functionalized compounds without protecting functional groups.

Stereoselective Iterative Convergent Synthesis of Z-Oligodiacetylenes from Propargylic Dithioacetals

A series of (t)Bu-substituted Z-oligodiacetylenes (Z-ODAs) are synthesized from the reactions of allenyl/propargylic zinc reagents, obtained from the corresponding propargylic dithiolanes and BuLi, with dithiolane-substituted propargylic aldehydes followed by stereospecific elimination of β-thioalkoxy alcohols under Mitsunobu conditions. The stereochemical assignments are based on NOE experiments. The X-ray structure of the hexamer further supports the Z configuration for each of the double bonds in these ODAs. The photophysical properties of these Z-ODAs have been examined and are compared with known related E- and Z-ODAs with different substituents.

Synthesis, Photophysics, Electrochemistry and Electrogenerated Chemiluminescence of PEG-Modified BODIPY dyes in Organic and Aqueous Solutions

A set polyethylene glycol (PEG) appended BODIPY architectures (BOPEG1 - BOPEG3) have been prepared and studied in CH2Cl2, H2O:CH3CN (1:1) and aqueous solutions. BOPEG1 and BOPEG2 both contain a short PEG chain and differ in substitution about the BODIPY framework. BOPEG3 is comprised of a fully substituted BODIPY moiety linked to a PEG polymer that is roughly 13 units in length. The photophysics and electrochemical properties of these compounds have been thoroughly characterized in CH2Cl2 and aqueous CH3CN solutions. The behavior of BOPEG1 - BOPEG3 correlates with established rules of BODIPY stability based on substitution about the BODIPY moiety. ECL for each of these compounds was also monitored. BOPEG1, which is unsubstituted at the 2- and 6-positions dimerized upon electrochemical oxidation while BOPEG2, which contains ethyl groups at the 2- and 6-positions, was much more robust and served as an excellent ECL luminophore. BOPEG3 is highly soluble in water due to the long PEG tether and demonstrated modest ECL activity in aqueous solutions using tri-n-propylamine (TPrA) as a coreactant. As such, BOPEG3 represents the first BODIPY derivative that has been shown to display ECL in water without the need for an organic cosolvent, and marks an important step in the development of BODIPY based ECL probes for various biosensing applications.