Synthesis of Aziridine‐ and Oxirane‐2‐phosphonates Spiro‐Fused with Oxindoles

Asymmetric Synthesis of Spirooxindoles via Nucleophilic Epoxidation Promoted by Bifunctional Organocatalysts

“…The given stereochemical outcomes are assigned upon a thorough comparison of the reported experiments, analytical data, and a quantum mechanical ab initio calculation of chiroptical properties. Specifically, the major diastereomers were identified as the trans products by comparing the spectroscopic analyses of each isolated compound with the corresponding data already reported in literature [ 26 ], while the (2′ S ,3′ S ) configuration was assigned to the major enantiomer of trans - 12h (see the stereochemistry analysis section below).…”

“…Likewise, Feng and co-workers investigated a Co(acac) 2 - N,N ′-dioxide-catalyzed Darzens reaction to afford benzyl-substituted trans -spirooxirane-oxindoles [ 10 ], while, more recently, Wong has focused his efforts on the use of (R)-BINOL and Ti(iOPr) 4 as catalysts reaching a high level of stereoselectivity involving chiral sulfur ylides in situ generated from camphor-derived sulfonium salts [ 24 ]. Conversely, less explored have been the stereoselective epoxidation of α-ylidenoxindoles with peroxide, which even though these furnished the titled products with excellent diastereomeric ratios, provided the corresponding spiroepoxides only with moderate to good enantioselectivity [ 25 , 26 , 27 ].…”

“…In the past few years, we have been engaged in the development of the nucleophilic epoxidation of α-ylidenoxindoles as well as in the improvement of the corresponding organocatalytic version [ 25 , 26 ], which mostly relies on the catalyst’s ability to install in the transition state a strong network with substrate and oxidizing agent ( Figure 1 A). Pursuing our research and prompted by the continuous interest concerning spiroepoxy derivatives, we envisaged enhancing the previously reported procedure by introducing further additional groups capable of installing more H-bonds inside the substrate/catalyst/oxidant system by modifying both the substrate and the catalyst.…”

Isatin derivatives in reactions with phosphorus(III–V) compounds

“…97 Isatins also easily participate in Horner-WadsworthEmmons reactions, which was demonstrated for the case of bis(diethoxyphosphoryl)methane, 103 using isatin derivatives substituted both at the nitrogen atom and in the aromatic ring, and resulting in the preparation of a series of indolecontaining vinylphosphonates 95 (Scheme 43). …”

Recent Advances in Asymmetric Organocatalytic Construction of 3,3′‐Spirocyclic Oxindoles

“…Recently, Loreto disclosed anther straightforward approach to spiro epoxy oxindoles by the epoxidation of methyleneindolinones (Scheme ) 40. Encouraged by this study, Gasperi developed the enantioselective version of this reaction by an asymmetric catalytic modification of the Weitz–Scheffer epoxidation of methyleneindolinones 41.…”