Pd-catalyzed enantioselective intramolecular Heck reaction to access disubstituted dihydroisoquinolinone with a terminal olefin

Palladium-Catalyzed Asymmetric Cross-Coupling Reactions of Cyclobutanols and Unactivated Olefins

“…We proposed a plausible reaction mechanism based on the above experiments and previous literature (Figure c). , First, oxidative addition of Pd(0) with 1a affords arylpalladium species A , which then undergoes an intramolecular Heck-type reaction to form chiral species B . Ligand exchange affords species C , which gives an intermediate D by β-carbon elimination.…”

“…Various nucleophiles, such as alkyl­(aryl) halides, alkenyl triflate, and organoboronic acids, have been applied in highly enantioselective aryl-alkylation, aryl-arylation, aryl-alkenylation reactions of unactivated olefins. Moreover, our laboratory has introduced the use of Pd and Xu-Phos complexes ,, in combination with organoboronic acids, alkynes, and ortho -ethynylanilines , to provide expedient access to various chiral benzene-fused cyclic compounds through the dicarbofunctionalization of alkenes. As a continuation of our ongoing research in the palladium-catalyzed dicarbofunctionalization of alkenes through cascade Heck reactions and inspired by the ring-opening reactions of cyclobutanol, we conceived the combination of cascade Heck reactions with a C–C bond cleavage process that, if successful, which would offer a potential complementary approach to construct C­(sp 2 /sp 3 )–C­(sp 3 ) bonds that exist in an array of valuable chemicals.…”

Enantioselective difunctionalization of alkenes by a palladium-catalyzed Heck/borylation sequence

“…Over the past few years, we have been focusing on the development of chiral sulfonamide phosphine ligands (Sadphos) for transition-metal-catalyzed asymmetric reactions. 13,15 Consequently, we examined the performance of a series of Sadphos (PC-Phos, Xiang-Phos, Ming-Phos and Xu-Phos) in this asymmetric reaction. The reaction using Ming-Phos ( N -Me-M1) as the chiral ligand could provide the desired product in 81% yield with 60% ee , whereas the use of PC-Phos and Xiang-Phos still failed to improve the enantioselectivity.…”

“… 11 Tong et al developed a Pd-catalyzed asymmetric vinylborylation of ( Z )-1-iodo-dienes with B 2 Pin 2 for enantioselective construction of 3,3-disubstituted tetrahydropyridines. 12 On the basis of these findings and the studies toward asymmetric cascade Heck reactions in our group, 13 we tended to exploit a highly enantioselective Heck/borylation sequence for the construction of the C–B bond starting from alkene-tethered aryl iodides and boronic esters. However several issues make the protocol challenging: (1) a direct Miyaura-type borylation seems to have an edge; 14 (2) competitive side reactions such as the reductive Heck reaction and carboiodination should be avoided; 13 a , b (3) the transmetalation step may take place prior to the alkene insertion, which could alter the steric environment and affect the enantioselectivity.…”

A palladium-catalyzed sequential Heck coupling/C–C bond activation approach to oxindoles with all-carbon-quaternary centers

“…Transition-metal-catalyzed selective C–C bond activation is one of the most challenging tasks in organic chemistry owing to its high bond energy and has received considerable attention in the past decades. 15 Activation of C–C bonds realizes C–C bond cleavage, 16 and subsequent functionalization allows the construction of various compounds. In most cases, C–C bond cleavage can be initiated by oxidative addition and β-carbon elimination.…”