Selective Synthesis of Secondary Alkylboronates: Markovnikov-Selective Hydroboration of Vinylarenes with Bis(pinacolato)diboron Catalyzed by a Nickel Pincer Complex

Abstract

A nickel pincer complex bearing a β-aminoketonato-based O,N,P-tridentate ligand (1a) has been employed for the highly Markovnikov-selective hydroboration of vinylarenes using bis­(pinacolato)­diboron. This reaction proceeds smoothly under mild reaction conditions and affords the corresponding Markovnikov products in good to high yield.

Modulation of Metal Species as Early Control Point for Ni-catalyzed Stereodivergent Semihydrogenation of Alkynes with Water

“…Although more experimental supports are awaited to uncover the detailed mechanism, a general scenario could be delineated based on the above results and relative literatures 31,32,[42][43][44][45][46][47][48][49][50] (Figure 1i of the Z-alkene to the Ni-H species assisted by alkyne precursor would occur in the late stage of the reaction, followed by isomerization process resulting in slight stereo-impurity. We propose that isomerization of a vinyl Ni(I) species is responsible for the E-selectivity observed in this approach, the speci c oxidation state at Ni could provide an opportunity for isomerization 42,43 .…”

Cross‐Coupling Reactions of Aryl Halides with Primary and Secondary Aliphatic Alcohols Catalyzed by an O,N,N‐Coordinated Nickel Complex

“…2 and 3). These results indicate that the C−O bond forming reaction is likely catalyzed by nickel boryl species derived from 1 b , 2 , and KO t ‐Bu, [15d] although more detailed studies are required for a definitive understanding of the exact mechanism of the present reaction.…”

“…Very recently, we have demonstrated the well‐defined β‐aminoketonato‐based O , N , P ‐coordinated tridentate nickel complex 1 a serves as a catalyst in the highly Markovnikov‐selective hydroboration of vinylarenes with bis(pinacolato)diboron (B 2 pin 2 , 2 ) (Scheme 1). [15d,16] This study encouraged us to explore applications using systems comprised of a nickel complex ( 1 ), 2 , and a base. During attempts to expand our previous work, we examined the borylation reaction using aryl halides and discovered that the O , N , N ‐coordinated nickel complex 1 b showed high catalytic activity for the cross‐coupling of aryl halides with primary and secondary aliphatic alcohols without the need for a phosphine ligand or a photoredox catalyst.…”

Saturated Boronic Acids, Boronates, and Trifluoroborates: An Update on Their Synthetic and Medicinal Chemistry

“…[240] This transformation was the first example of asymmetric hydroboration of unactivated terminal alkenes. Also, several papers reported Co-, [244][245][246] Fe-, [247] and Nicatalyzed [248] "Markovnikov" boronations; however, the scope of these transformations were limited by styrene derivatives.…”