Iridium(III)‐Catalyzed CH Amidation of Arylphosphoryls Leading to a P‐Stereogenic Center

Abstract

Direct CH amidation of arylphosphoryl compounds has been developed by using an Ir(III) catalyst system under mild conditions. A wide range of substrates could be employed with high functional-group tolerance. This procedure was successfully applied for the first time to the asymmetric reaction giving rise to a P-chirogenic center with a high diastereomeric ratio of up to 19:1 (90 % de).

Dual role of carboxylic acid additive: mechanistic studies and implication for the asymmetric C–H amidation

“…Another significant aspect of this study is that our proposal on the dual role of acid additive is verified based on the observed asymmetric induction. Interestingly, while the amidation of phosphinamides was efficient in the presence of PivOH additive as seen in our previous study, 13 the reaction was rather sluggish by using dipivaloyl L-tartaric acid additive (5e, 44%).…”

“…Coupling constants, J, were reported in hertz unit (Hz). 13 C NMR was fully decoupled by broad-band proton decoupling. Signals of 13 C spectra of carbon atoms adjacent to phosphorus atom of organophosphorus compounds appeared as doublet with varied coupling constants between C and P (J CeP ).…”

“…12 Recently, we developed the Ir(III)-catalyzed direct C(sp 2 )eH amidation of arylphosphoryl compounds using organic azides as the amino source. 13 Under the optimized conditions, diarylphosphoryl compounds (RAr 2 P]O, RsAr) were readily amidated in excellent yields as a racemic mixture (Scheme 2, in case of RsPh). Herein, an interesting issue was how to achieve stereoselective CeH amidation of prochiral diarylphosphoryl starting materials to give rise to P-chirogenic center.…”

“…13 While moderate to high diastereoselectivity was attained, one drawback in this approach was the required installation of expensive and stubborn chiral auxiliaries. Therefore, the development of enantioselective CeH amidation of prochiral diarylphosphoryls (RAr 2 P]O, RsAr) is highly desirable to afford chiral phosphorus compounds.…”

Pd-catalyzed enantioselective C–H arylation of phosphinamides with boronic acids for the synthesis of P-stereogenic compounds

“…The most commonly used methods for the preparation of Pstereogenic molecules have mainly relied on resolution, [24][25][26] chiral-auxiliary-aided asymmetric synthesis, [27][28][29][30][31][32][33][34] and asymmetric lithiation-trapping reactions. [35][36][37][38] Other alternative methods include the NHC-catalyzed desymmetrization of bisphenolic phosphinates, 39 the metal-catalyzed asymmetric cross-coupling of phosphines or phosphine oxides, [40][41][42][43][44][45] hydrophosphination of olefins, 46 addition reactions of phosphorus nucleophiles, 47,48 and olefin metathesis of divinyl phosphinates.…”