A chiral Lewis acid accelerated 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). Control experiments and theoretical calculations revealed that a synergistic effect of the counterion and water was critical for the regio‐ and enantioselective protonation after the [1,2]‐phospha‐Brook rearrangement.

An efficient catalytic asymmetric cyclization/inverse‐electron‐demand hetero‐Diels‐Alder cascade reaction of β,γ‐unsaturated α‐ketoesters with alkyl amides or alcohols were accomplished. The process was based on the utilization bimetallic catalyst system with achiral gold(I) catalyst and chiral N,N′‐dioxide/Ni(II) catalyst, delivering a variety of fused bicyclic N,O‐acetals or O,O‐acetals in up to 99% yield and 99% ee with >19:1 dr under mild reaction conditions. Based on the control experiments and previous studies, a possible reaction pathway of bimetallic relay catalysis cascade reactions was presented.magnified image

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.

Asymmetric catalytic allylation of halo-substituted ketones and ketoesters was accomplished to yield a number of homoallylic tertiary alcohols in excellent reactivity and enantioselectivity. In the presence of chiral In III /N,Nʹ-dioxide catalyst, unusual α-selective allylation of γ-substituted potassium allyltrifluoroborates to ketones was demonstrated. The control experiments and DFT calculation reveal that chiral In III /N,Nʹ-dioxide catalyst plays dual-tasking roles: the formation of allylindium species via transmetalation and Lewis acid activation. A possible reaction pathway was provided to understand α-selectivity over γ-selectivity.

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.