697302-50-4Relevant articles and documents
Dimeric boroles: Effective sources of monomeric boroles for heterocycle synthesis
Su, Xiaojun,Baker,Martin, Caleb D.
, p. 126 - 131 (2019/12/30)
Monomeric boroles have been gaining attention as reagents for the synthesis of heterocycles due to their ability to insert atoms into the BC4 ring in a single step. Although unique boron frameworks can be accessed via this methodology, the products feature aryl substitution on the carbon centers as steric bulk is required to preclude borole dimerization. This work demonstrates that insertion chemistry is possible with Diels-Alder dimeric boroles and that such reactivity is not exclusive to monomeric boroles with bulky groups. With 1-phenyl-2,3,4,5-tetramethylborole dimer, the formal 1,1-insertion of a nitrene and sulfur generate the six-membered aromatic 1,2-azaborine and 1,2-thiaborine, respectively. The isolation of the 1,2-thiaborine enabled the synthesis of an η6-chromium complex. Benzophenone and diphenylketene readily insert a CO unit to generate BOC5 seven-membered rings confirming dimeric boroles can serve as monomeric synthons in 1,2-insertion reactions. An epoxide did not furnish the anticipated eight-membered BOC6 ring, instead provided a bicyclic system with a BOC3 ring. The insertion chemistry was demonstrated with two other borole dimers featuring different substitution with diphenylketene as a substrate. This work elevates borole insertion chemistry to a new level to access products that do not require bulky substitution.
A halogenophilic pathway in the reactions of transition metal carbonyl anions with [(η6-iodobenzene)Cr(CO)3]
Sazonov, Petr K.,Ivushkin, Vasiliy A.,Khrustalev, Victor N.,Kolotyrkina, Natal'Ya G.,Beletskaya, Irina P.
, p. 13392 - 13398 (2014/11/07)
The paper provides the first example of formal nucleophilic substitution by the halogenophilic pathway in Cr(CO)3 complexes of haloarenes with metal carbonyl anions. All metal carbonyl anions examined attack [(η6-iodobenzene)Cr(CO)3] at halogen, which is shown by aryl carbanion scavenging with t-BuOH. The reaction with K[CpFe(CO) 2] gives only the dehalogenated arene, but the reaction with K[Cp*Fe(CO)2] (Cp* = η5-C 5Me5) results in nucleophilic substitution to give [(η6-C6H5FeCp*(CO) 2)Cr(CO)3]. Reaction with Na[Re(CO)5] quantitatively gives the iodo(acyl)rhenate anion Na[(η6-C 6H5C(O)ReI(CO)4)Cr(CO)3] and in the case of K[Mn(CO)5] a mixture of σ-aryl complexes [(η6-C6H5Mn(CO)5)Cr(CO) 3] and K[(η6-C6H5Mn(CO) 4I)Cr(CO)3]. An analogous rhenium complex Na[(η6-C6H5Re(CO)4I)Cr(CO) 3] is formed from the initial iodo(acyl)rhenate upon prolonged standing at 20 °C, and its structure (in the form of [NEt4] + salt) is established by X-ray diffraction analysis. The reaction of [(η6-chlorobenzene)Cr(CO)3] with K[CpFe(CO) 2], in contrast, proceeds by the common SN2Ar mechanism.
[2+4] Cycloaddition of η6-(styrene)chromium tricarbonyl and conjugated dienes
Artemov,Sazonova,Revin,Rybkin,Lazarev,Faerman
, p. 2103 - 2106 (2012/09/22)
Cycloaddition of η6-(styrene)chromium tricarbonyl to hexa-2,4-diene or cyclopentadiene afford the Diels-Alder adducts with retention of the Cr(CO)3 group, whereas cyclohexa-1,3-diene undergoes aromatization to give η6-(ben
