Lewis acid mediated vinyl-transfer reaction of alkynes to N-alkylimines by using the N-alkyl residue as a sacrificial hydrogen donor.

A variety of N-alkyl-α,α-dichloroaldimines were vinylated by terminal acetylenes in the presence of Lewis acids such as In(OTf)3 or BF3 ⋅OEt2 and hexafluoroisopropanol (HFIP) as an additive. The reaction proceeds at ambient temperature and leads to geometrically pure allylic ß,ß-dichloroamines. This approach is complementary to previously reported transition-metal-catalyzed vinyl-transfer methods, which are not applicable to aliphatic imines and are restricted to imines that contain an electron-withdrawing nitrogen substituent. In the present approach, terminal alkynes were used as a source of the vinyl residue, and the N-alkyl moiety of the imine acts as a sacrificial hydrogen donor. The additional advantage of this methodology is the fact that no external toxic or hazardous reducing agents or molecular hydrogen has to be used. This new methodology nicely combines a C(sp(2) )C(sp) bond formation, hydride transfer, and an unusual cleavage of an unactivated CN bond, thereby giving rise to functionalized primary allylic amines. A detailed experimental study supported by DFT calculations of the mechanism has been done.

Synthesis of isomerically pure anti-anthradithiophene derivatives.

The regiospecific total synthesis and characterization of anti-isomers of 2,8-dialkylanthradithiophenes are described. The "anti" structure of the ADT derivatives is demonstrated by (13)C NMR as well as single crystal X-ray diffraction.

Dimers of anthrathiophene and anthradithiophene derivatives: synthesis and characterization.

Synthesis, isolation, and characterization of derivatives of an anthrathiophene dimer (TOTBAT) and of anthradithiophene oligomers (ADTO), possessing octylthiophene units on their backbone, are described. These semiconductors are prepared through oxidative copper(II) chloride coupling. The spectroscopic properties and stability of these newly synthesized semiconductors were evaluated and supported by quantum-chemical calculations.