Reversible switching between housane and cyclopentanediyl isomers: an isonitrile-catalysed thermal reverse reaction

Abstract

The photo-isomerization of an isolable five-membered singlet biradical based on C, N, and P ([TerNP]2CNDmp, 2a) selectively afforded a closed-shell housane-type isomer (3a) by forming a transannular P-P bond. In...

Access to Benzo‐ and Naphtho‐Azaphospholes via C−H Bond Activation of Aryl‐Substituted Isonitriles

“…As previously shown, a variety of isonitriles are able to insert into a PÀ N bond of biradical 1 yielding the corresponding fivemembered hetero-cyclopentanediyls (2R, for example R = 2,6dimethylphenyl = Dmp, Scheme 1 and Scheme 3). [42,45,46] To investigate the various equilibrium reactions and housane formation (4R) under irradiation (Scheme 1), depending on the phenyl substituent of the isonitrile, both electron-withdrawing and electron-donating functional groups were used in paraposition of the phenyl substituent (R' = tBu, NMe 2 ). As depicted in Scheme 3, a set of seven differently aryl-substituted isonitriles were used in the reaction with biradical 1.…”

“…Synthesis of the hetero-cyclopentanediyls 2 and utilisation as a molecular switch to generate 4 (R' = tBu, Me 2 N, H). Adduct products 3 can be formed in a reversible equilibrium reaction [45,46] and in the case of aryl substituted isonitriles (bearing CÀ H bonds in ortho-position) biradical 2 can undergo CÀ H activation leading to the formation of azaphospholes 5. Scheme 2.…”

Synthesis of Bicyclic P,S-Heterocycles via the Addition of Thioketones to a Phosphorus-Centered Open-Shell Singlet Biradical

“…Pnictogen-centered open-shell singlet biradicals − of the type [E­(μ-NR)] 2 (E = P, As, Sb, Bi; R = Ter; Ter = terphenyl = 2,6-dimesitylphenyl; [P­(μ-NR)] 2 = 1Ter ) have been used for some time to activate small molecules containing single and multiple bonds (Scheme ). ,− Among others, heterocumulenes such as CO 2 and CS 2 , bearing a carbon–chalcogen double bond, can be activated by 1Ter and converted to their corresponding addition products.…”

A cyclic thioketone as biradical heterocyclopentane-1,3-diyl: synthesis, structure and activation chemistry

“…That is, under irradiation, a transannular P-P bond is formed, resulting in a housane type closed-shell molecule (species 6X). 9,12,[15][16][17][18] When the irradiation is switched off, the system thermally reacts back, the P-P bond is cleaved and biradical 5X is recovered.…”

“…Phosphorus-heterocyclic species such as 1 and 5X belong to the class of open-shell singlet biradicals, 11,15,16,[18][19][20][21][22][23][24][25][26][27][28][29][30] which means that the spin density is exact zero at each point in space but yet they can be utilized as trapping reagents of highly reactive molecular fragments 31 and molecular switches [16][17][18] besides the activation of small molecules as discussed above. 9 Therefore, based on the known properties of 5O, we wanted to investigate how the molecular switching properties as well as the molecular activation chemistry change when the oxygen is formally exchanged for a sulphur atom, i.e., an analogous cyclic biradical thioketone of type 5S (Scheme 1) should be synthesized and its reactivity investigated.…”