Tetrasubstituted allenes via the palladium-catalysed kinetic resolution of propargylic alcohols using a supporting ligand

Recent Advances in Catalytic Nonenzymatic Kinetic Resolution of Tertiary Alcohols

“…43 In 2019, Ma, Qian, Guo, and co-workers developed a highly effective KR of racemic tertiary propargylic alcohols 83 for the construction of tetrasubstituted 2,3-allenoic acids 86 triggered by palladium and Brønsted acid cooperative catalysis (Scheme 16c). 44 Addition of achiral PPh 3 as the supporting ligand was demonstrated to be pivotal to this process. Remarkably, the recovered alcohols 83 with moderate ee values underwent a second KR to afford the other enantiomer of the tetrasubstituted 2,3-allenoic acids with excellent enantioselectivity.…”

Halogenated salt assisted Cu-catalyzed asymmetric 1,4-borylstannation of 1,3-enynes: enantioselective synthesis of allenylstannes

“…1 Compared to classically predominant strategies, e.g. resolution 2 and stereospecific transformation of chiral substrates, 3 accessing chiral axial allenes via efficient asymmetric catalysis (transition metal catalysis and organocatalysis) of prochiral substrates is a long-standing challenge and highly desirable.…”

One-pot synthesis of multi-substituted conjugated dienones by trapping allene carbocations with active ylides

“…5 The nucleophiles include heteroatom nucleophiles, 6 a electron-rich arenes, 6 b enols, 6 a enamines, 6 c vinyl thioether, 6 d halides, 6 e aziridines 6 f and so on. In recent decades, highly efficient transition metal-catalyzed cross coupling reactions of propargylic alcohol derivatives with various nucleophiles were also developed by Ma, 7 Murakami, 8 and other groups. 9…”