Construction of Multisubstituted Tetrahydropyrans by a Domino Oxa-Michael/Tsuji–Trost Reaction

Aerobic Allylic Amination Catalyzed by a Pd(OAc)2/P(OPh)3 System with Low Catalyst Loading

A Pd(OAc)₂/P(OPh)₃ combination catalyzed Tsuji-Trost-type allylic amination under aerobic conditions. Both aromatic and aliphatic secondary amines were transformed into the corresponding allylic amines with a tiny amount of the catalyst system (typically 0.02 mol % Pd), only when allylic phosphates were employed as electrophiles. Other typical electrophiles, such as allylic acetate and carbonate, were marginally reactive. A Pd(0) complex, Pd[P(OPh)₃]₃, formed in situ was suggested as an active species by mechanistic experiments.

Palladium-Catalyzed Asymmetric Decarboxylative [4+2] Dipolar Cycloaddition of 4-Vinyl-1,3-dioxan-2-ones with α,β-Disubstituted Nitroalkenes Enabled by a Benzylic Substituted P,N-Ligand

The Pd-catalyzed asymmetric [4+2] cycloaddition reaction of an aliphatic 1,4-dipole with singly activated electron-deficient alkenes is realized for the first time, enabled by using a newly developed benzylic substituted P,N-ligand, affording tetrahydropyrans having three continuous chiral centers in high yields with high diastereo- and enantioselectivities. The rational transition states of the reaction as well as the role of the benzylic chiral center are proposed.

Modular synthesis of the pyrimidine core of the manzacidins by divergent Tsuji-Trost coupling

The design, development and application of an efficient procedure for the concise synthesis of the 1,3-syn- and anti-tetrahydropyrimidine cores of manzacidins are reported. The intramolecular allylic substitution reaction of a readily available joint urea-type substrate enables the facile preparation of both diastereomers in high yields. The practical application of this approach is demonstrated in the efficient and modular preparation of the authentic heterocyclic cores of manzacidins, structurally unique bromopyrrole alkaloids of marine origin. Additional features of this route include the stereoselective generation of the central amine core with an appending quaternary center by an asymmetric addition of a Grignard reagent to a chiral tert-butanesulfinyl ketimine following an optimized Ellman protocol and a cross-metathesis of a challenging homoallylic urea substrate, which proceeds in good yields in the presence of an organic phosphoric acid.