Gold-Catalyzed Access to Isophosphinoline 2-Oxides

Abstract

Gold­(I)-catalyzed reactions of electron-poor alkynes are still a challenging process. A straightforward synthesis of phosphorus-based heterocycles, namely, 2-phenyl 1H-isophosphinoline 2-oxides 1, is reported. The reaction used PPh3AuCl precatalyst in combination with triflic acid under microwave activation and afforded isophosphinoline 2-oxides 1 in moderate to quantitative yields through a fully regioselective 6-endo-dig hydroarylation cyclization, paving the way toward an effective synthesis of phosphorus heterocycles.

Biologically relevant surrogates of coumarins: 2-phenyl H-isophosphinoline 2-oxides with antibacterial activity

“…Figure 2 The logical route to stable surrogates of coumarins The synthetic route already described in JOC 2021 [22], for the preparation of 2-phenyl H-isophosphinoline 2-oxide derivatives 4, is depicted in Scheme 1. The first step began with the preparation of diversely substituted phenyl(arylmethyl)phosphinic acids 5 easily obtained in good yields from the reaction of various arylmethyl halides and phenylphosphinic acid using hexamethyldisilazane as coreagent.…”

One‐Pot Synthesis of Selected P‐Vinylbenzyls under Solvent‐Free Conditions

“…[5][6][7] Despite its remarkable value, only a few syntheses strategies have been developed for the preparation of phosphorylated or phosphonylated vinylbenzyls, and related molecules. [5][6][7][8]13,[15][16][17][18][19][20] The aforementioned compounds' syntheses were realized by the formation of the bond between phosphorus with benzyl carbon atoms via nucleophilic substitution adapting Michaelis-Arbuzov or Michaelis-Becker reaction (Scheme 1).…”

“…[20] The P-vinylbenzyls derivatives of 4-vinylbenzyl chloride are known molecules and have been described in the literature. [8,13,[15][16][17][18][19][20]23] Some of them are commercially available. [23] However, no analog example with P-CH 2 fragment in ortho or meta position compared to the vinyl group has been reported.…”

“…Additionally, they use hexamethyldisilazane (HMDS) as a silylating agent. [19] Most of already reported syntheses of P-vinylbenzyls are based on multi-step chemical transformations, which had the disadvantages of harsh reaction conditions, air sensitive and toxic materials, relatively expensive reagents or catalysts, poor product yields, long reaction times, and tedious separation procedures. The inaccessibility of convenient synthetic methodologies is probably the most important reason for the lack of products of P-vinylbenzyls and finding its applications.…”

“…Malysheva's team demonstrated the original synthetic methodology for syntheses P‐vinylbenzyls based on white and red phosphorus (Scheme 1; method D) [20] . The P‐vinylbenzyls derivatives of 4‐vinylbenzyl chloride are known molecules and have been described in the literature [8,13,15–20,23] . Some of them are commercially available [23] .…”