A New Route to Phosphaalkene Chelate Complexes: SET Deoxygenation of Oxaphosphirane Complexes Followed by Intramolecular CO Substitution

Abstract

Contentsp.2 Crystal data for 1a,b p.3 Crystal structure determination and molecular structure of 1a (Figure S1) p.4 Crystal structure determination and molecular structure of 1b (Figure S2)

Synthesis of P-CPh3 Substituted Spirooxaphosphirane Complexes: Steric Effects Dominate the Product Formation

“…31 P­{ 1 H} NMR spectroscopy of the reaction mixture showed a signal at 195.3 ppm ( 1 J W,P = 255.1 Hz) which is in the expected range for complex 7 . − Unfortunately, complexes 3 and 7 could not be separated due to very similar solubilities, and further attempts to use column chromatography were met with limited success due to their instability on the solid phase.…”

“…In the case of monocyclic oxaphosphirane complexes IV , the synthetic breakthrough came with the advent of Li/Cl phosphinidenoid complexes as P 1 building blocks due to their high reactivity toward aldehydes and ketones combined with functional group tolerance. , For example, studies on acid-induced ring opening (i) and ring expansion (ii) have demonstrated that they are valuable building blocks for unusual heterocyclic P-ligands and, hence, deserve further investigations. Furthermore, the possibility to remove the ring oxygen atom via a reductive single electron transfer (SET) reaction using Ti­(III) reagents is of particular interest as it had opened a new route to end-on phosphaalkene complexes …”

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

“…12a: 1 H NMR (CDCl 3 ) δ 0.30 (s, 9 H, SiMe 3 ), 0.34 (s, 9 H, SiMe 3 ), 2.25 (d, 1 H, 2 J P,H = 4.0 Hz, CH), 3.57 (d, 1 H, 2 J H,H = 15.0 Hz, CH 2 ), 3.85 (dd, 1 H, 2 J H,H = 15.0 Hz, 2 J P,H = 11.3 Hz, CH 2 ); 13 C{ 1 H} NMR (CDCl 3 ) δ 2.6 (d, 3 J P,C = 3.2 Hz, SiMe 3 ), 2.9 (d, 3 J P,C = 1.9 Hz, SiMe3), 35.0 (d, 1 J P,C = 26.5 Hz, PCH 2 ), 43.3 (d, 1 J P,C = 12.9 Hz, PCH), 79.0−82.0 (m, C(CF 3 ) 2 ), 121.7 (q, 1 J F,C = 284.5 Hz, CF 3 ), 122.1 (qd, 1 J F,C = 285.5 Hz, 3 J P,C = 4.5 Hz, CF 3 ), 196.2 (dq sat , 1 J W,C = 126.1 Hz, 2 J P,C = 7.8 Hz, 6 J F,C = 1.5 Hz cis-CO), 199.0 (d, 2 J P,C = 31.0 Hz, trans-CO); 19 F NMR (CDCl 3 ) δ −76.3 (qd 4 J F,F = 9.9 Hz, 4 J P,F = 3.4 Hz), −77.8 (qd 4 J F,F = 9.9 Hz, 4 J P,F = 1.9 Hz). 29 Si NMR (CDCl 3 ) δ = 2.81 (d, 2 J P,Si = 6.8 Hz), -0.07 (d, 2 J P,Si = 7.6 Hz); 31 P{ 1 H} NMR (CDCl 3 ) δ 198.2 ppm (s sat , 1 J W,P = 297.6 Hz).…”

“…Similarly, 1,2-oxaphosphetane complexes III were unknown, and only one attempt was described, proposing a 1,2-oxaphosphetane complex as a reactive intermediate, but leading finally to a mixture of a phosphirane and a dioxaphospholane complex. 2 In recent years, we demonstrated that Li/Cl phosphinidenoid complexes are versatile building blocks leading to various new ring systems with aldehydes, 3 ketones, 4 imines, 5 or alkynes. 3 However, also 1,1′-bifunctional acyclic complexes were obtained in good yields and with high selectivity by formal insertion into the O−H bond of alcohols.…”

“…In recent years, we demonstrated that Li/Cl phosphinidenoid complexes are versatile building blocks leading to various new ring systems with aldehydes, ketones, imines, or alkynes . However, also 1,1′-bifunctional acyclic complexes were obtained in good yields and with high selectivity by formal insertion into the O–H bond of alcohols. , This versatile nucleophilic building block also enabled access to 1,2-oxaphosphetane complexes VIa – c via formal insertion into a C–O bond of the epoxides, displaying additionally high group tolerance (Scheme ).…”