Phosphine-Catalyzed Vinylation at Low Acetylene Pressure.

The vinylation of various nucleophiles with acetylene at a maximum pressure of 1.5 bar is achieved by organocatalysis with easily accessible phosphines like tri--butylphosphine. A detailed mechanistic investigation by quantum-chemical and experimental methods supports a nucleophilic activation of acetylene by the phosphine catalyst.

Hydrogenation of Secondary Amides using Phosphane Oxide and Frustrated Lewis Pair Catalysis.

The metal-free catalytic hydrogenation of secondary carboxylic acid amides is developed. The reduction is realized by two new catalytic reactions. First, the amide is converted into the imidoyl chloride by triphosgene (CO(OCCl ) ) using novel phosphorus(V) catalysts.

FLP-catalysis meets hydrogen-bond activation.

The potential of two chiral amidines and three non-chiral boranes in the metal-free hydrogen activation was explored. The resulting chiral amidiunium borohydride salts were investigated in asymmetric hydrogenation reactions of ketimines, activated double bonds and dehydro amioacid esters.

Frustrated Lewis Pair Catalyzed Hydrogenation of Amides: Halides as Active Lewis Base in the Metal-Free Hydrogen Activation.

A method for the metal-free reduction of carboxylic amides using oxalyl chloride as an activating agent and hydrogen as the final reductant is introduced. The reaction proceeds via the hydrogen splitting by B(2,6-F-CH) in combination with chloride as the Lewis base. Density functional theory calculations support the unprecedented role of halides as active Lewis base components in the frustrated Lewis pair mediated hydrogen activation.

Frustrated Lewis Pair-Catalyzed Cycloisomerization of 1,5-Enynes via a 5-endo-dig Cyclization/Protodeborylation Sequence.

The first frustrated Lewis pair-catalyzed cycloisomerization of a series of 1,5-enynes was developed. The reaction proceeds via the π-activation of the alkyne and subsequent 5-endo-dig cyclization with the adjacent alkene. The presence of PPh3 was of utmost importance on the one hand to prevent side reactions (for example, 1,1-carboboration) and on the other hand for the efficient protodeborylation to achieve the catalytic turnover.