Palladium-catalyzed asymmetric [3+2] cycloaddition to construct 1,3-indandione and oxindole-fused spiropyrazolidine scaffolds

Abstract

A facile and versatile Pd/L8-catalyzed asymmetric [3+2] cycloaddition of 3-diazooxindoles with a new vinylcyclopropane to construct spiropyrazolidine derivatives has been developed.

Synthetic applications of vinyl cyclopropane opening

“…Later on, the same research group reported a similar reaction using with 2-vinyl-spiroindanones. 26 Again, chiral imidazoline-phosphines were the best ligands, achieving the spiro indanone derivatives in excellent yields but only moderate enantioselectivities. A three component coupling between terminal alkynes 50, arynes 52 and vinyl cyclopropanes 16 was reported by Werz in 2015.…”

Utilizing Palladium‐Stabilized Zwitterions for the Construction of N‐Heterocycles

“…Later, the Shi group showed that the activated cyclopropane 36 containing an indan‐1,3‐dione moiety could undergo a range of asymmetric cycloadditions with diazooxindoles utilizing L9 as the ligand (Scheme ) …”

“…Later,t he Shi group showed that the activated cyclopropane 36 containing an indan-1,3-dionem oiety could undergo a range of asymmetric cycloadditions with diazooxindoles utilizing L9 as the ligand (Scheme 22). [28] Nickel has been found to catalyze the [3+ +2] cycloaddition reactiono fv inylcyclopropanes with imines. [29] However,i nc ontrast to the metal-containing zwitteriont hat is predominantly thought to be the reactive intermediate in palladium-catalyzed cycloadditions, the nickel-catalyzed process is proposed to proceed via nickelocycle 38.U se of Ni(cod) 2 and 1,2-bis(dimethylphosphino)ethane (dmpe) promotes the reactionb etween vinylcyclopropane 37 and av ariety of N-tosyl aryl-and alkylimines,f urnishing av ariety of pyrrolidine products in excellent yields and with good to excellent diastereoselectivities (Scheme23).…”

Base‐Catalyzed Formal [3+2] Cycloaddition of Diazooxindoles with Oxazol‐5‐(4H)‐ones

“…Since then, the [3+2] cycloaddition reactions of diazooxindoles with acetylenes, enaminones, phosphonium ylides, and arynes have been developed individually. Recently, Shi established the catalytic asymmetric [3+2] cycloaddition of diazooxindoles with vinyl cyclopropanes and 2‐vinylspiro[cyclopropane‐1,2′‐indene]‐1′,3′‐dione [Scheme , Equation (2) and Equation (3)] , . Despite the advances that have been achieved in the [3+2] cycloaddition of diazooxindoles, the design and exploration of new [3+2] cycloaddition reactions of diazooxindoles is still highly desirable.…”