P-Functionalized tetrathiafulvalenes from 1,3-dithiole-2-thiones?

Abstract

Synthesis of mono- and bisphosphanylated 1,3-dithiole-2-thiones is presented, including phosphite-mediated reductive C,C coupling reactions. Computational studies point to a spirothiaphosphirane and a S-heterocyclic carbene as key intermediates.

Accurate Ring Strain Energies of Unsaturated Three-Membered Heterocycles with One Group 13–16 Element

“…One of the most widely used parameters is the nucleus-independent chemical shift (NICS) which allows the aromatic character to be quantified so that the more negative the NICS value, the higher the aromatic character. As isotropic NICS values calculated at the ring centroid are strongly influenced by the σ-contributions, NICS(1) (computed at 1 Å above and below the ring centroid) are usually employed . The NICS(1) values for 1 El were calculated at the standard B3LYP/6311+G­(d,p) level for elements of the second to fourth rows and using the def2-TZVPP basis set for elements of the fifth and sixth rows.…”

“…As isotropic NICS values calculated at the ring centroid are strongly influenced by the σ-contributions, NICS(1) (computed at 1 Å above and below the ring centroid) are usually employed . The NICS(1) values for 1 El were calculated at the standard B3LYP/6311+G­(d,p) level for elements of the second to fourth rows and using the def2-TZVPP basis set for elements of the fifth and sixth rows. At first sight, a clear correlation between NICS(1) and RSE is observed (Figure ), with almost linear character for elements having (groups 15–16) or not having LPs (groups 13–14), if 1 N and 1 O* are excluded.…”

CHNO isomers and derivatives – a computational overview

“…The computed stability sequence 13a 4 14a 44 17a does not agree with the aromaticity order 14a 4 17a 4 13a according to both NICS(1) (À6.58 o À3.41 o À1.39 ppm, respectively) and NICS(1) zz values (À2.78 o À0.91 o 0.08 ppm, respectively); compare this with NICS(1) = À10.22 ppm and NICS(1) zz = À29.36 ppm for benzene at the same level. 30 The low (yet significant) aromaticity of 13a points to an important contribution of a charge-separated resonance structure with all three nitrogen lone pairs delocalized at the oxygen atoms, as supported by their computed highly negative (natural) charge (q N (O) = À0.564 e), which is even higher than that in 17a (q N (O) = À0.442 e), in agreement with the reported LP(N)p*(CQO) electron donation. 28…”

Toward a 1,4-Diphosphinine-Based Molecular CPS-Ternary Compound

“…As previously described by us, the 1,3-dithiol-2-thione I can be deprotonated with a strong base and reacts with chlorophosphanes to get backbone-phosphanylated 1,3-dithiol-2-thiones . Following this protocol, compound 1 was obtained after deprotonation of I with n -butyllithium ( n BuLi) in tetrahydrofuran (THF) and subsequent reaction with (Et 2 N) 2 PCl at −95 °C and slow warming to ambient temperature (16 h, 84% yield; Scheme ).…”

“…Next, the desulfurization reaction of the 1,4-diphosphinine 12 with an excess of Me 3 P was computationally addressed. A related reaction between methyl phosphite [(MeO) 3 P] and either parent 1,3-dithiole-2-thione or derivatives with P-substituents in the backbone was recently reported, and the intermediacy of σ 5 λ 5 -thiaphosphiranes arising from the chelotropic reaction of the P­(III) reagent with the CS functionality was demonstrated. Also, the Me 3 P-mediated reductive dimerization of ketones was shown to start by the initial chelotropic formation of σ 5 λ 5 -oxaphosphirane .…”