Nickel-catalyzed switchable 1,3-dienylation and enantioselective allenylation of phosphine oxides

Abstract

The development of general catalytic methods for the regio- and stereoselective construction of phosphoryl derivatives from identical substrates remains a formidable challenge in organic synthesis. Enabled by the newly developed BDPP-type ligands, we disclosed a nickel-catalyzed allenylation of phosphine oxides rationally and predictably, allowing the construction of versatile chiral allenylphosphoryl derivatives with high enantiopurity (up to 94% e.e.). Alternatively, using an achiral phosphine ligand dcypbz under acidic conditions, we achieved a regiochemical switch of the 1,3-dienylation to afford functionalized phosphinoyl 1,3-butadienes (up to 93% yield). The salient features of this method include switchable reactivity, broad substrate scope, readily available feedstock, single-step preparation, and high asymmetric induction.

Recent advances in nickel-catalyzed propargylic substitution

“…In 2022, Guo and coworkers unveiled a method for nickel-catalyzed allenylation of phosphine oxides (Scheme 19). 32 This approach facilitates the assembly of versatile chiral allenylphosphoryl derivatives with high enantiopurity, reaching up to 94% enantiomeric excess. The success of this process is attributed to the use of newly developed BDPP-type ligands.…”

Recent Advances in Nickel‐Catalyzed Synthesis of Allenes: New Insights and Perspectives

“…Guo and co‐workers in 2022 using propargylic carbonates as allenylating reagents reported a nickel‐catalyzed enantioselective allenylation of phosphine oxides, giving a series of versatile chiral allenylphosphoryl frameworks with excellent enantioselectivity (Scheme 6). [26] Key to the success of this transformation was the development of a novel BDPP‐type ligand and the use of HCO 2 Li as an additive. Broad substrate scope and good functional group compatibility were observed in both propargylic carbonates and phosphine oxides.…”

Regiodivergent and Stereoselective Synthesis of Highly Substituted 1,3-Dienes via Arylative Acyloxy Migration of Propargyl Esters

“…The stereochemistry of this class of tetrasubstituted 1,3dienes was determined by X-ray diffraction (44). Meanwhile, 2°alkyl groups at the propargylic position or alkyne terminus, such as cyclopropyl (36,39), cyclobutyl (35), cyclohexyl (40,41), and six-membered rings with a functional group (37,38), could smoothly participate in the reaction. Next, we focused on the scope of diaryliodonium salts with propargyl ester 45 as the pilot substrate (Table 3).…”

“…As a result of these efforts, readily available propargyl esters have been well-established as an appealing class of synthetic intermediates for accessing functionalized conjugated dienes via transition-metal catalysis. − Notably, electrophilic metals (e.g., Au, Pd, or Ru) catalyzing the rearrangement of propargyl esters through two classic 1,2 vs. 1,3-acyloxy migration routes constitute a powerful and useful tool for this event. − However, this strategy is strictly limited to furnishing mono-, di-, or trisubstituted conjugated dienes with key protonation as the terminal step (Figure c, type I). To date, the rearrangement of propargyl esters involving C–C bond formation as carbofunctionalization of the propargyl moiety with an external carbon-based reagent in delivering highly substituted 1,3-dienes is still undiscovered (Figure c, type II).…”