An Isolable Mixed P,S‐Bis(ylide) as an Asymmetric Carbon Atom Source

Synthesis, Structure, and Reactivities of Iminosulfane‐ and Phosphane‐Stabilized Carbones Exhibiting Four‐Electron Donor Ability

“…The central carbon atom of 1 – 3 bears a large negative charge ( 1 – 3 : −1.38 e), which is similar to that of BPC ( A : −1.43 e, −1.55 e17), BChCs ( B : −1.24 e; C : −1.20 e; D : −1.25 e), and PSC ( E : −1.36 e) 1. 10, 11 The Wiberg bond index values of iSPCs for P→C ( 1 : 1.26; 2 : 1.24; 3 : 1.22) are lower than those for S→C ( 1 : 1.30 2 : 1.31 3 : 1.34), which is in contrast to the trend observed in PSC F (P→C: 1.42, S→C: 1.21) and suggests the existence of strong back donation (n–σ* interaction) from the lone pairs of the central carbon to the adjacent σ* orbitals of the sulfur ligand 11b. Both carbon lone pairs of 3 are stabilized through interactions with σ*(SN), σ*(SC Ph ), and σ*(PC Ar ), as determined by NBO second‐order perturbation analysis (Table S5 in the Supporting Information).…”

“…11 This distance indicates a relatively strong S→C bond in 3 . The P→C bond length of 3 is longer than that in A (1.635 Å), but is similar to that of F (1.667 Å) 11b. 16 The angle at the central carbon increases slightly from salt 3⋅ H (123.6°) to 3 (125.6°).…”

“…In particular, nσ C interacts with σ*(SN) (11.5 kcal mol −1 ), σ*(SC Ph ) (10.8 kcal mol −1 ), and σ*(PC Ar ) (19.3 kcal mol −1 ), whereas nπ C interacts with σ*(SN) (12.9 kcal mol −1 ), σ*(SC Ph ) (28.0 kcal mol −1 ), and σ*(PC Ar ) (25.5 kcal mol −1 ). The total stabilization energy of n–σ*S ( E total =63.2 kcal mol −1 ) is larger than that of n–σ*P ( E total =44.8 kcal mol −1 ), which is in contrast to diamido‐stabilized F (n–σ*S: E total =31.4 kcal mol −1 , n–σ*P: E total =66.0 kcal mol −1 ) 11b. These results suggest that, through the n–σ* interaction, the iminosulfane ligand is more strongly bound to the central carbon atom than the sulfide ligand of PSCs…”

“…Selected bond lengths and angles of 3 and 3⋅ H are listed in Table 1, together with data for A , B , and F and their protonated salts A⋅ H, B⋅ H, and F⋅ H for comparison 1a. 10a, 11b, 16 The P→C (1.663 Å) and S→C (1.602 Å) bond lengths of 3 are significantly shorter than those of the corresponding cationic salt 3⋅ H (P→C: 1.734 Å; S→C: 1.658 Å; Δ P→C =0.071 Å, Δ S→C =0.056 Å). This observation is different from that for F (P→C: 1.667 Å; S→C: 1.684 Å; Δ P→C =0.023 Å, Δ S→C =0.003 Å).…”

Phosphine/Sulfoxide‐Supported Carbon(0) Complex

“…The P1−C1 bond length [1.6563(13) Å] in 2 is significantly shorter than in 1 [1.7190(15) Å] and the value remains slightly longer than those reported for CDPs (1.584–1.648 Å) . The S1−C1 bond length also undergoes significant shortening upon deprotonation [from 1.6539(15) Å in 1 to 1.5929(14) Å in 2 ], this value is the shortest S−C bond length reported to date in the sulfur‐stabilized carbone series (1.602–1.713 Å) ,. The S1−O1, S1−C16, and S1−C22 bond lengths get slightly longer (Δ S−X max=+0.02 Å).…”