Bidentate Lewis Acids Derived from o-Diethynylbenzene with Group 13 and 14 Functions.

Starting from 1,2-diethynylbenzene, a series of bidentate Lewis acids was prepared by means of hydrometalations, in particular hydrosilylation, hydroboration, hydroalumination and terminal metalation based on group 13 and 14 elements. In the case of terminal alkyne metalation, the Lewis-acidic gallium function was introduced using triethylgallium under alkane elimination. A total of six different Lewis acids based on a semiflexible organic scaffold were prepared, bearing -SiClMe , -SiCl Me, -SiCl , -B(C F ) , -AlBis (Bis=bis(trimethylsilyl)methyl) and -GaEt as the corresponding functional units.

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics.

The amide moiety of peptides can be replaced for example by a triazole moiety, which is considered to be bioisosteric. Therefore, the carbonyl moiety of an amino acid has to be replaced by an alkyne in order to provide a precursor of such peptidomimetics. As most amino acids have a chiral center at C, such amide bond surrogates need a chiral moiety.