Asymmetric [3+2] Cycloaddition of Olefins with Morita–Baylis–Hillman Carbonates Catalyzed by BINOL-Based Bifunctional Phosphine

Abstract

We have developed a series of novel BINOL-based phosphines. These bifunctional organocatalysts can be used in the [3+2] cycloaddition of electron-deficient olefins and Morita–Baylis–Hillman (MBH) carbonates. Moderate to excellent yields (up to >99%) and good to excellent enantioselectivities (up to 95% ee) can be obtained in the cycloaddition reaction of maleimides and MBH carbonates. The application of these novel phosphines can be further extended to the asymmetric synthesis of chiral spirooxindoles (up to 85% ee). The results in this study indicate that the BINOL moiety plays an important role in stereocontrol.

Organocatalytic Regio- and Enantioselective [3 + 2]-Annulations of Ninhydrin-Derived Morita–Baylis–Hillman Carbonates with 3-Methyleneoxindoles

“…In particular, Lu et al reported the first [3 + 2]-annulation of MBH carbonates with the aid of phosphane . Subsequently, organocatalytic asymmetric [3 + 2]-annulation of MBH carbonates garnered particular attention. − Independently, Chen’s group has gracefully developed new MBH carbonates from isatins, which were successfully involved in organocatalytic stereoselective [3 + 2]-annulations. − Notably, the organocatalytic stereoselective annulation of MBH carbonates has offered a key platform for the construction of functionalized enantioenriched carbo- and heterocycles . Although great progress has been achieved in this field, the core framework of MBH carbonates is monotonous and limited to the classical MBH adducts from aldehyde (Scheme A) and isatins (Scheme B).…”

Asymmetric Reactions Catalyzed by Chiral Tertiary Phosphines

“…Cui and coworkers have developed a series of novel BINOL‐based phosphines, and applied the catalyst 177 to catalyze the [3+2] cycloaddition reactions of electron‐deficient olefins and MBH carbonates. [ 61 ] Moderate to excellent yields (up to >99%) and good to excellent enantioselectivities (up to 95% ee) can be obtained in the cycloaddition reaction of maleimides and MBH carbonates (Scheme 42). The application of these novel phosphines can be further extended to the asymmetric synthesis of chiral spirooxindoles (up to 85% ee) (Scheme 42).…”

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

“…[211] In the preparation of spirocyclic compounds from 3-alkylidenenindolones, phosphines are also used as organocatalysts. [212,213] The cycloaddition of symmetric aryl ketones 164 to derivatives of 3-alkylidenenindolone 165 is catalyzed by tributylphosphine PBu 3 and leads to spirocyclic compounds 166. The diastereoselectivity of spirocyclization is moderate and does not exceed 9 : 1.…”

“…[213] In the synthesis of indolones spiro-fused with cycloalkanes in the [ good enantioselectivity (74 -85 %) in the presence of the catalyst 170 (Scheme 45). [212] The intermolecular Rauhut-Currier cross-reaction of benzylidene cyclopentenone 171 or 2-cyclopentenone (or 2-cyclohexenone) 172 with 3-(dicyano)methylidene-2-oxindoles 30 or 173 is carried out with the aid of a double catalytic system that combines 2- (Scheme 46,a). A sharp decrease in the yield (up to 42 %) of the spiro-fused heterocycle 178 is observed in the reaction of cyclohexenone 172 (n = 2) with indolone 173 (R=H, R 1 = Me) when using β-nitrostyrene as an activated olefin (R 2 = Ph).…”

“…Spirooxindole 169 is formed in good yield (69–93 %) and with relatively good enantioselectivity (74–85 %) in the presence of the catalyst 170 ( Scheme 45). [212] …”