A computational study of the reaction mechanism of aryl propiolates with various radicals is examined employing DFT and coupled-cluster methods at the DLPNO-CCSD(T)/cc-pVTZ//M062X-6-311G(d,p) level. Computations demonstrated that the reaction mechanism...

A computational study on the reaction mechanism of the effective synthesis of sulfonated benzo[b]oxepinones and chromanes by radical cascade cyclization is carried out employing the density functional theory (DFT). Based on our computations, the rate‐determining step is the formation of arylsulfonyl radical for the reaction scheme. Our calculations show that the reaction of 1,8‐ and 1,7‐enynes with arylsulfonyl radical proceeds by forming more thermodynamically stable intermediates. Therefore, 1,8‐enynes prefer 7‐exo‐trig cyclization, while 1,7‐enynes prefer 6‐exo‐trig cyclization. Our computations are consistent with experimental results of the radical cascade cyclization of 1,8‐ and 1,7‐enynes. Moreover, our computations show that if the reaction is carried out in a proton‐free solvent, the elimination product can be obtained from the cascade radical cyclization of the 1,7‐enyne.

A computational study of the pyrolysis of 1,5-diaryl-1,2,5triazapentadiene derivatives is carried out employing density functional theory (DFT) and high-level coupled-cluster methods, such as coupled-cluster singles and doubles with perturbative triples [DLPNO-CCSD(T)]. Our results demonstrate that the reaction proceeds through the products formed by the electrocyclization, as opposed to the mechanism suggested by Mcnab (J. Chem. Soc., Chem. Commun. 1980, 422-423), in which the reaction proceeds by starting via formation of the iminyl radicals. Our results demonstrate that the products formed by electrocyclization are responsible for the formation of iminyl radicals, contrary to homolysis of NÀ N bond of 1,5-diaryl-1,2,5triazapentadiene derivatives proposed by Mcnab. Besides, our results showing that the reaction starts with the electrocyclization very well clarify why the formation of ortho-cyclization product, contrary to ipso-cyclization from 1,5-diaryl-1,2,5-triazapentadiene derivatives as the main product. Therefore, our results are in agreement with the experimental results for pyrolysis of 1,5-diaryl-1,2,5-triazapentadiene derivatives.

1-Vinil 5-heksenil radikallerinin reaksiyon mekanizması için hesaplamalı bir çalışma, yoğunluk fonksiyonel teorisi kullanılarak gerçekleştirildi. Sonuçlarımız, termodinamik olarak kararlı 6-endo-trig halka kapanma ürününün oluşumuna yönelik reaksiyonun hem 5-ekso-trig hem de 6-endo-trig halka kapanma modları üzerinden ilerleyebileceğini gösterdi. Ayrıca, hesaplamalarımız, 5-ekso-trig halka kapanma ara ürününün kararlı olması durumunda, 6-endotrig halka kapanma ürününün oluşumundan 5-ekso-trig modun sorumlu olacağını gösterdi.

A computational study for 2,2‐azobis (isobutyronitrile) (AIBN)‐induced remote trifluoromethyl‐alkynylation of thioalkynes is carried out employing the density functional theory (DFT). According to our computations, the decomposition of AIBN, which is the initial step of the radicalic reaction, include the highest reaction energy step and indicate that the rate‐determining step is the decomposition of AIBN for the reaction scheme. Our computations show that the reaction can also proceed through the vinyl radicals 12 and 18 as well as the vinyl radicals 3 and 10 suggested by Zhu and co‐workers. The computations are compatible with experimental data. Moreover, our computations provide useful insight into the radicalic mechanism of AIBN‐induced remote trifluoromethyl‐alkynylation of thioalkynes.