Asymmetric [4 + 2] cycloaddition synthesis of 4<i>H</i>-chromene derivatives facilitated by group-assisted-purification (GAP) chemistry

Rouh, Hossein; Tang, Yao; Zhang, Sai; Ali, Ahmed I. M.; Surowiec, Kazimierz; Unruh, Daniel K.; Li, Guigen

doi:10.1039/d1ra08323f

Cited by 4 publications

(3 citation statements)

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“…After the complete consumption of starting materials of the reaction, the measurements of chemical yields were also based on crude 31 P NMR analysis by using triphenylphosphine as the internal standard in which the 31 P NMR peak appears at -5 ppm. In all cases, for all aromatic substrates with either neutral, electron-withdrawing, or electron-donating groups, the estimated yields arrange from 60% to 70%, which is within a similar range of isolated yields as our previous synthesis.…”

Section: Synthesis and Stereoselectivity Determinationmentioning

confidence: 99%

“…General synthesis of salicyl N-phosphonyl imines (1a-1d) and 2,3-dihydrobenzofuran (3a-3e) and their analytical data, 1 H NMR spectra, 13 C NMR spectra, and 31 P NMR spectra. 31 P NMR spectra for diastereoselectivity determination. (Supplementary Materials)…”

Section: Data Availabilitymentioning

confidence: 99%

“…In the past several years, our lab has established the Group-Assisted Purification (GAP) chemistry and technology by taking advantage of new N-phosphonyl and N-phosphinyl imine reagents and their usages for asymmetric synthesis [22][23][24][25][26][27][28][29][30][31]. The existence of GAP functions in chiral imine starting materials can avoid the formation of oily and sticky products and instead result in crystalline solids, including chiral or achiral aggregates.…”

Section: Introductionmentioning

confidence: 99%

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Aggregation-Induced Synthesis (AIS): Asymmetric Synthesis via Chiral Aggregates

Rouh

Tang

et al. 2022

Research

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A new chiral aggregate-based tool for asymmetric synthesis has been developed by taking advantage of chiral aggregates of GAP (Group-Assisted Purification) reagents, N-phosphonyl imines. This tool was proven to be successful in the asymmetric GAP synthesis of functionalized 2,3-dihydrobenzofurans by reacting salicyl N-phosphonyl imines with dialkyl bromomalonates in various cosolvent systems. The chiral induction can be controlled by differentiating between two asymmetric directions simply by changing the ratios of cosolvents which are commonly adopted in AIE (aggregation-induced emission) systems. The formation of chiral aggregates was witnessed by a new analytical tool—aggregation-induced polarization (AIP). The present synthetic method will be broadly extended for general organic synthesis, particularly, for asymmetric synthesis and asymmetric catalysis in the future.

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Section: Synthesis and Stereoselectivity Determinationmentioning

confidence: 99%

Section: Data Availabilitymentioning

confidence: 99%