Rhodium-catalyzed Oxidative Decarbonylative Of Aromatic Aldehydes And Nickel-catalyzed Cis-hydrogenation Of Internal Alkynes

Olefins exist in a large number of drugs, materials, and natural compounds. Currently widely used method for the synthesis of olefins include: various elimination/condensation, Witting reaction, Heck coupling(decarboxylative Heck type coupling), alkene metathesis, alkyne reduction and others. Combining our research interest in decarbonylation of aldehydes and Heck coupling, a rhodium catalyzed oxidative decarbonylative Heck coupling of aromatic aldehydes with terminal olefins was designed. Since the previous reported olefin synthesis most often provide trans alkenes selectively, we hope to develop a cheap catalyst and cheap raw material to synthesize cis olefins.This dissertation involves two parts:(1) rhodium-catalyzed oxidative decarbonylative Heck-type coupling of aromatic aldehydes with terminal alkenes;(2) stereoselective nickel-catalyzed transfer hydrogenation of internal alkynes affording cis-alkenes.Most organic compounds contains different types of sp2 C-H bonds, so direct sp2 C-H bond transformation into C-X(X = C, N, O, P, S, etc.) bond overriding pre-functionalization would short the process, improve the atomic economy and economic value, and reduce the cost of organic synthesis. In the first part, a rhodium-catalyzed oxidative decarbonylative Heck-type coupling of aromatic aldehydes and terminal alkenes to afford 1,2-disubstituted alkenes with good regioand E-selectivity is developed. This reaction employs readily available aromatic aldehydes as the aryl electrophile counterpart and relies on selected acyl chloride as the crucial additive to activate the rhodium catalyst precursor.The cis-alkenes widely exist in a variety of drugs and materials, but the methods for selective synthesis of thesis cis alkenes were much less. In the second part, various reduction methods of internal alkynes to afford cis-alkenes are introduced, and an efficient method to transform internal alkynes into cis-alkenes was established using cheap nickel catalyst and assisted by Lewis acids, with DMF as reductant. Cheap catalyst, cheap reductant and readily available starting materials would guarantee its further application for the synthesis of cis alkenes both in laboratory and industry.