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A highly enantioselective tandem Pudovik addition/[1,2]‐phospha‐Brook rearrangement of α‐alkynylketoamides with diarylphosphine oxides was achieved with a N,N′‐dioxide/ScIII complex as the catalyst. This protocol features broad substrate scope, high regio‐ and enantioselectivity, and good functional‐group compatibility, providing a straightforward route to various trisubstituted allenes with a diarylphosphinate functionality in good yields with high enantioselectivities (up to 97 % yield, 96 % ee). Control experiments and theoretical calculations revealed that a synergistic effect of the counterion and water was critical for the regio‐ and enantioselective protonation after [1,2]‐phospha‐Brook rearrangement. The synthetic utility of this methodology was demonstrated by the conversion of products into complex bridged polycyclic architectures through intramolecular dearomatizing arene/allene cycloaddition. [ABSTRACT FROM AUTHOR]

Axial Chiral Allenes, Lewis Acid Catalysis, Phospha-Brook Rearrangement, Synergistic Effect, Water Keywords: Axial Chiral Allenes; Lewis Acid Catalysis; Phospha-Brook Rearrangement; Synergistic Effect; Water EN Axial Chiral Allenes Lewis Acid Catalysis Phospha-Brook Rearrangement Synergistic Effect Water 1 1 1 06/29/22 20220704 NES 220704 B A chiral Lewis acid accelerated b asymmetric Pudovik addition/[1,2]-phospha-Brook rearrangement is described by Shunxi Dong, Qian Peng, Xiaoming Feng, and co-workers in their Research Article (e202203650). Back Cover: Catalytic Regio- and Enantioselective Protonation for the Synthesis of Chiral Allenes: Synergistic Effect of the Counterion and Water (Angew. [Extracted from the article]

Keywords: Axial Chiral Allenes; Lewis Acid Catalysis; Phospha-Brook Rearrangement; Synergistic Effect; Water EN Axial Chiral Allenes Lewis Acid Catalysis Phospha-Brook Rearrangement Synergistic Effect Water 1 1 1 06/29/22 20220704 NES 220704 B Eine chirale Lewis-Säure b beschleunigt die asymmetrische Pudovik-Addition/[1,2]-Phospha-Brook-Umlagerung, wie Shunxi Dong, Qian Peng, Xiaoming Feng und Mitarbeiter in ihrem Forschungsartikel berichten (e202203650). Axial Chiral Allenes, Lewis Acid Catalysis, Phospha-Brook Rearrangement, Synergistic Effect, Water Rücktitelbild: Catalytic Regio- and Enantioselective Protonation for the Synthesis of Chiral Allenes: Synergistic Effect of the Counterion and Water (Angew. [Extracted from the article]

Chiral molecules with multiple stereocenters are widely present in natural products and pharmaceuticals, whose absolute and relative configurations are both critically important for their physiological activities. In spite of the fact that a series of ingenious strategies have been developed for asymmetric diastereodivergent catalysis, most of these methods are limited to the divergent construction of point chirality. Here we report an enantioselective and diastereodivergent synthesis of trisubstituted allenes by asymmetric additions of oxazolones to activated 1,3-enynes enabled by chiral phosphoric acid (CPA) catalysis, where the divergence of the allenic axial stereogenicity is realized by modifications of CPA catalysts. Density functional theory (DFT) calculations are performed to elucidate the origin of diastereodivergence by the stacking- and stagger-form in the transition state (TS) of allene formation step, as well as to disclose a Münchnone-type activation mode of oxazolones under Brønsted acid catalysis. Despite of the high demand of chiral allenes, their asymmetric synthesis remains a challenge for organic chemists. Here, the authors report a stereodivergent synthesis of trisubstituted allenes via asymmetric additions of oxazolones to activated 1,3-enynes enabled by modification of chiral phosphoric acid catalysts. [ABSTRACT FROM AUTHOR]