Ke-Yin Ye

Iridium-Catalyzed Allylic Vinylation and Asymmetric Allylic Amination Reactions with o-Aminostyrenes

An Ir-catalyzed allylic vinylation reaction of allyl carbonates with o-aminostyrene derivatives has been realized, providing skipped (Z,E)-diene derivatives. With (E)-but-2-ene-1,4-diyl dimethyl dicarbonate as the substrate, an efficient enantioselective synthesis of 1-benzazepine derivatives via an Ir-catalyzed domino allylic vinylation/intramolecular allylic amination reaction has been developed. Mechanistic studies of the allylic vinylation reaction have been carried out, and the results suggest that the leaving group of the allylic precursor plays a key role in directing the reaction pathway. Screening of various allylic precursors showed that Ir-catalyzed reactions of allyl diethyl phosphates with o-aminostyrene derivatives proceed via an allylic amination pathway. A subsequent ring-closing metathesis (RCM) reaction of the amination products led to a series of enantiomerically enriched 1,2-dihydroquinoline derivatives. Their utility is indicated by an asymmetric total synthesis of (-)-angustureine.

Palladium‐Catalyzed Oxidative Carbonylation of N‐Allylamines for the Synthesis of β‐Lactams

β-Lactam scaffolds are considered to be ideal building blocks for the synthesis of nitrogen-containing compounds. A new palladium-catalyzed oxidative carbonylation of N-allylamines for the synthesis of α-methylene-β-lactams is reported. DFT calculations suggest that the formation of β-lactams via a four-membered-ring transition state is favorable.

Ruthenium-catalyzed regioselective allylic trifluoromethylthiolation reaction.

An efficient Ru-catalyzed regioselective allylic trifluoromethylthiolation reaction of allylic carbonates was developed. The linear allylic trifluoromethyl thioethers were obtained in 52-91% yields. Mechanistic investigation revealed that this reaction proceeds via a double allylic trifluoromethylthiolation sequence.

An Iridium(I) N‐Heterocyclic Carbene Complex Catalyzes Asymmetric Intramolecular Allylic Amination Reactions

A chiral iridium(I) N-heterocyclic carbene complex was reported for the first time as the catalyst in the highly enantioselective intramolecular allylic amination reaction. The current method provides facile access to biologically important enantioenriched indolopiperazinones and piperazinones in good yields (74-91 %) and excellent enantioselectivities (92-99 % ee). Preliminary mechanistic investigations reveal that the C-H activation occurs at the position ortho to the N-aryl group of the ligand.

Coupling of Carbon Monoxide with Nitrogen Monoxide at a Frustrated Lewis Pair Template

Coupling of carbon monoxide with nitrogen monoxide was achieved at a frustrated Lewis pair template. This unique reaction uses hydride as an auxiliary, which reductively activates carbon monoxide at the frustrated Lewis pair. The CO/NO coupling reaction then takes place through a pathway involving a radical reaction in which the hydrogen atom auxiliary is eventually removed again.

Synthesis of 1-[bis(trifluoromethyl)phosphine]-1'-oxazolinylferrocene ligands and their application in regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates.

Summary A class of novel, easily accessible and air-stable 1-[bis(trifluoromethyl)phosphine]-1’-oxazolinylferrocene ligands has been synthesized from ferrocene. It became apparent that these ligands can be used in the regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates in a highly efficient manner. Excellent regio- and enantioselectivity could be obtained for a wide range of substrates.