The efficient and selective synthesis of enantioenriched α-aryl carbonyl compounds is important owing to their presence in marketed pharmaceuticals, bioactive compounds, and natural products (Figure ). The conventional approach to this motif involves direct α-arylation techniques using transition metal catalysts and base-mediated enolate chemistry. This strategy for accessing α-aryl carbonyl compounds can pose limitations when synthesizing tertiary stereocenters as they are base sensitive and prone to racemization by enolization. Therefore, the synthesis of enantiopure tertiary α-aryl ketones is synthetically challenging and requires procedures that will eliminate the need for an interfering strong base. The semipinacol rearrangement, when involving a 1,2-aryl migration, can be harnessed to synthesize α-aryl carbonyl compounds and is a viable alternative to enolate arylation chemistry. It has been shown that the addition of various radicals to the olefin of an allylic alcohol can produce racemic α-aryl ketones via a radical 1,2-aryl migration mechanism. In a few cases, it has been shown that a single electron transfer (SET) event can occur to generate a carbocation before aryl migration ensues. The few enantioselective semipinacol rearrangement protocols that involve aryl migration involve enantiospecific nucleophilic displacement of an enantioenriched halonium, or hypervalent iodine species and create β-keto functionalised products. Related polar rearrangements involving 1,2-aryl shifts have employed chiral Brønsted acids, which instead involve non-covalent interactions between the substrate and catalyst. In the context of hydro-semipinacol rearrangements with allylic alcohols, the addition of a proton or hydrogen atom to the C=C bond can be used to instigate reactivity (Figure ). The latter has been demonstrated via metal-hydride hydrogen atom transfer (MHAT) using a superstoichiometric quantity of Fe(acac)3 with a silane, or photocatalytically using a cobalt catalyst. The carbon-centered radical generated after the HAT step undergoes a neophyl-type rearrangement to afford racemic ketones with electron-deficient aryl rings migrating preferentially. Rendering this process enantioselective is intrinsically challenging although a modest degree of stereoretention has been demonstrated with enantioenriched allylic alcohols in the cobalt system. Alternatively, direct protonation of the olefin generates a carbocation intermediate, which in the context of aryl rearrangement leads to selective migration of the most electron-rich arene. This polar approach has enabled the development of catalytic enantioselective hydro-semipinacol rearrangements most commonly using Brønsted acid catalysis. These methodologies all feature aliphatic carbon migrations to heteroatom-stabilized or tertiary carbocations leading to ring-expanded products. Therefore, secondary carbocations and 1,2-aryl shifts have not been realized within this framework. In fact, we are aware of only one reported example where a 1,2-aryl migration occurs in a polar hydro-semipinacol rearrangement with allylic alcohols. This scarcity may be related to the incompatibility of α-vinylbenzyl alcohols with the strongly acidic conditions typically required to facilitate such rearrangements. One approach that combines the milder reaction conditions of MHAT with the migratory tendencies of cationic intermediates invokes a radical-polar crossover process. This tactic has been deployed extensively in cobalt-catalyzed olefin hydrofunctionalizations to construct C-O, C-N, C-S, and C-C bonds as racemic mixtures. Recently, photochemical and electrochemical procedures that negate the requirement for a stoichiometric oxidant in this manifold have been disclosed. Generally, some of these methods might involve a cobalt(IV) intermediate, which undergoes displacement by the incoming nucleophile and presents an opportunity for asymmetric induction. However, this mode of reactivity has only been harnessed for highly enantioselective transformations in five previous reports by Pronin, Shigehisa, and Zhang. In particular, the cobalt-catalyzed radical-polar crossover reactions of allylic alcohols were previously investigated by Pronin and co-workers which focused on the reactivity profile of aliphatic systems. A competition between hydroalkoxylation and semipinacol rearrangement pathways was controlled by the choice of cobalt-salen complex. Further work demonstrated that a chiral catalyst with extended aromatic systems could deliver epoxide products with high enantioselectivity. Conversely, substrates that underwent the semipinacol rearrangement with 1,2-alkyl migration showed low levels of enantiocontrol. Here, we demonstrate that an alkylcobalt(IV) species generated from an allylic alcohol can behave as a stereodefined surrogate for a secondary carbocation (Figure ). The subsequent asymmetric semipinacol rearrangement proceeds via 1,2-aryl migration to give ketones bearing tertiary arylated stereocenters.