Phosphine-Catalyzed (4 + 2) Annulation of δ-Sulfonamido-Substituted Enones with 1,1-Dicyanoalkenes: Synthesis of Piperidine Derivatives

Abstract

The δ-sulfonamido-substituted enones were employed as phosphine acceptor in phosphine-catalyzed (4 + 2) annulation of 1,1-dicyanoalkenes. They served as a four-membered synthon to react with 1,1-dicyanoalkenes under mild reaction conditions, producing piperidine derivatives in moderate to excellent yields with good to excellent diastereoselectivities.

Acidic Hydrogen‐Tethered Allylic Carbonates for Phosphine‐Catalyzed (4+2) Annulation of Sulfamate‐Derived Cyclic Imines

“…In order to develop new reactions, design and synthesis of new phosphine acceptors are highly desirable. In recent years, we synthesized several acidic hydrogen‐tethered electron‐deficient alkenes and used them as phosphine acceptors in nucleophilic phosphine catalysis (Scheme 1a) [2–5] . They exhibited intriguing reactivities under phosphine catalysis, reacting with several electrophiles such as acyclic N‐sulfonylimines, [2] sulfamate‐derived cyclic imines, [3] 1,1‐dicyanoalkenes [4] and azomethine imines [5] to implement annulation reactions for forming heterocyclic molecules (Scheme 1a).…”

“…In recent years, we synthesized several acidic hydrogen-tethered electron-deficient alkenes and used them as phosphine acceptors in nucleophilic phosphine catalysis (Scheme 1a). [2][3][4][5] They exhibited intriguing reactivities under phosphine catalysis, reacting with several electrophiles such as acyclic N-sulfonylimines, [2] sulfamate-derived cyclic imines, [3] 1,1-dicyanoalkenes [4] and azomethine imines [5] to implement annulation reactions for forming heterocyclic molecules (Scheme 1a). In these acidic hydrogentethered phosphine acceptors, the heteroatom-hydrogen group such as sulfonamido [2][3][4] and hydroxyl [5] can perform proton transfer to produce new reactive intermediate under phosphine catalysis for new reactions.…”

“…[2][3][4][5] They exhibited intriguing reactivities under phosphine catalysis, reacting with several electrophiles such as acyclic N-sulfonylimines, [2] sulfamate-derived cyclic imines, [3] 1,1-dicyanoalkenes [4] and azomethine imines [5] to implement annulation reactions for forming heterocyclic molecules (Scheme 1a). In these acidic hydrogentethered phosphine acceptors, the heteroatom-hydrogen group such as sulfonamido [2][3][4] and hydroxyl [5] can perform proton transfer to produce new reactive intermediate under phosphine catalysis for new reactions. [6] In principle, acidic carbon-hydrogen group can also perform proton transfer or deprotonation as those heteroatom-hydrogen group did, thus introduction of acidic carbon-hydrogen group into classical phosphine acceptors such as alkene, alkynes and allenes will be a nice strategy to design and find new phosphine acceptor.…”

“…These phosphines such as Ph 2 PMe, PhPMe 2 , Bu 3 P and Me 3 P led to the cycloaddition product 3 aa with 60, 59, 60 and 58% yields, respectively (entries 2-5). In addition, we found that dimethylaminopyridine (DMAP), 1,4diazabicyclo[2.2.2]octane (DABCO) and 1,8diazabicyclo [5,4,0]undec-7-ene (DBU) were disappointing in this reaction, only giving trace of product (entries 6-8). Having determined a promising phosphine, we next evaluated several solvents (entries 9-12).…”

Straight-chain ω-amino-α,β-unsaturated carbonyl compounds: versatile synthons for the synthesis of nitrogen-containing heterocycles via organocatalytic reactions

“…Soon after, a phosphine-catalyzed asymmetric tandem isomerization/[3 + 2] annulation sequence between β-sulfonamido-substituted α,β-unsaturated esters 1 and γ-substituted allenoates 41 was realized by Guo, Chen and coworkers (Scheme 15). 28 A series of chiral pyrrolines 42 (24 examples) were obtained in high yields (21-87%) and excellent Scheme 11 Phosphine-catalyzed [4 + 2] annulation between δ-sulfonamido-substituted enones and 1,1-dicyanoalkenes (Guo and Zheng, 2021 24 ). Scheme 12 Phosphine-catalyzed [3 + 2] annulation of β-sulfonamidosubstituted enones and sulfamate-derived cyclic imines (Guo and Xiao, 2019 25 ).…”