C-Trifluoromethyl-Substituted 1,2-Oxaphosphetane Complexes: Synthetic and Structural Study

Abstract

Recently, the first synthetic route to 1,2-oxaphosphetane complexes was described, but the formation of too many isomers was a clear drawback and hampered further studies. Herein, we present significant advances with this problem using trifluoromethyl epoxide (4), 1,1′-bis­(trifluoromethyl) epoxide (5), and differently substituted Li/Cl phosphinidenoid complexes 1–3 (R = CH­(SiMe3)2, CPh3, C5Me5), thus giving 1,2-oxaphosphetane complexes 6–10 with high selectivity.

Oxophosphonium-alkyne cycloaddition reactions: reversible formation of 1,2-oxaphosphetes and six-membered phosphorus heterocycles

“…Given the importance of 1,2σ 5 λ 5 -oxaphosphetanes C as intermediates in the Wittig reaction , and the rich chemistry of 1,2σ 3 λ 3 -oxaphosphetanes B developed by the group of Streubel, − it is surprising that 1,2-oxaphosphetes have not yet been isolated. Keglevich and co-workers postulated 1,2σ 5 λ 5 -oxaphosphete intermediates in the reaction of phosphine oxides with the particularly electrophilic alkyne dimethylacetylenedicarboxylate .…”

Addressing the Nature of Phosphinidene Sulfides via the Synthesis of P−S Heterocycles

“…In this particular case, structural characterization of the first 1,2-oxaphosphetane [1] and NMR spectroscopic data [2] favoured the formation of the strained 4-membered PÀOh eterophosphete. [3][4][5][6][7][8][9] Although chemistry of the 1,2-oxaphosphetanes, either containing transition-metal stabilized P III (A) [10][11][12][13] or pentavalent phosphorus (B) [14][15][16][17] have been studied, the heavierc halcogen derivativesa re considerably underdeveloped in comparison. The most common examples of heterophosphetes containing heavierc halcogens are 1,2-thiaphosphetanes, which containa saturated 4-membered PSC 2 ring and ap entavalentp hosphorus atom (C & D).…”

Acid-Induced Reactions of 1,2-Oxaphosphetane Complexes

“…According to the 31 P NMR spectrum of the reaction solution the ratio was 10:0:60:30 in comparison to 29:4:48:19 in the original synthesis . The different ratio might be explained in terms of a lower rotational barrier of the P–C bond (to CH­(SiMe 3 ) 2 ) in the starting material ( 2b ) in comparison to the Li/Cl phosphinidenoid complex (in the former synthesis), thus leading to the preferred formation of more stable atropisomers.…”

“…Recently, we presented two different routes to 1,2σ 3 λ 3 -oxaphosphetane complexes starting from dichlorophosphane complexes VI and epoxides (Scheme , reaction v) or from the 2-iodoethoxyphosphane complex VII (reaction vi) . The first route showed a high regioselectivity for the reaction and was successfully employed especially in the case of alkyl-substituted epoxides.…”