1694-31-1Relevant articles and documents
Chemoselectivity in the Reactions of Acetylketene and Acetimidoylketene: Confirmation of Theoretical Predictions
Birney, David M.,Xu, Xiaolian,Ham, Sihyun,Huang, Xiaomeng
, p. 7114 - 7120 (1997)
Acetylketene (1) was generated by flash pyrolysis of 2,2,6-trimethyl-4H-1,3-dioxin-4-one (6). The selectivities of 1 toward a number of representative functional groups were measured for the first time in a series of competitive trapping reactions. The trend in reactivities toward 1 follows the general order amines > alcohols aldehydes ≈ ketones and can be rationalized by considering both the nucleophilicity and the electrophilicity of the reacting species. Alcohols show significant selectivity based on steric hindrance, with MeOH ≈ 1° > 2° > 3°. These selectivities are consistent with the activation energies and the pseudopericyclic transition structure previously calculated for the addition of water to formylketene. The results, presented here, of ab initio transition structure calculations for the addition of ammonia to formylketene are qualitatively consistent with the experimental trends as well. N-Propylacetacetimidoylketene (2) was generated by the solution pyrolysis of tert-butyl N-propyl-3-amino-2-butenoate (9a) and showed similar selectivity toward alcohols as opposed to ketones and similar steric discrimination toward alcohols. This is again in agreement with previous ab initio calculations. Taken together, these experimental trends in the reactivities of both 1 and 2 toward a variety of reagents provide strong, although indirect support for the planar, pseudopericyclic transition structures for these reactions which are predicted by ab initio calculations.
PORPHYRINS. 18. SYNTHESIS OF OCTAPROPYLPORPHYRIN BY THE METHOD OF MONOPYRROLE CYCLOTETRAMERIZATION OF 5-CARBOXY-2-METHOXYMETHYL-3,4-DIPROPYLPYRROLE. INVESTIGATION OF THE THERMOLYSIS OF meso-N-METHYLFORMALDIMINEOCTAPROPYLPORPHYRIN
Shul'ga, A. M.,Ponomarev, G. V.
, p. 748 - 753 (1984)
The synthesis of octapropylporphyrin on the basis of 5-carboxy-2-methoxymethyl-3,4-dipropylpyrrole was realized.It was demonstrated that in the thermolysis of meso-N-methylformaldimineoctapropylporphyrin, 31,51-cyclo-31-ethylidene- and 31,51-cyclo-31-ethyl-51-(N-methylimine) derivatives are also formed in addition to 31,51-cyclo-31-ethylheptapropylporphyrin.
Csp3-H monofluoroalkenylation via stereoselective C-F bond cleavage
Hu, Binjing,Hu, Ying,Li, Jie,Liu, Xingchen,Ren, Zhouyang
supporting information, p. 2734 - 2737 (2022/03/02)
A practical nickel- and photoredox-catalyzed Csp3-H monofluoroalkenylation through chelation-assisted Csp2-F bond cleavage of gem-difluoroalkenes for the synthesis of stereodefined tetrasubstituted fluoroalkenes has been developed. Moreover, the gem-difluoroalkenes can also undergo photoredox-catalyzed cascade twofold C-F diaminomethylation. This journal is
Visible-light-driven radical 1,3-addition of selenosulfonates to vinyldiazo compounds
Li, Weiyu,Zhou, Lei
supporting information, p. 6652 - 6658 (2021/09/10)
Herein, we report a visible-light-driven radical 1,3-selenosulfonylation of vinyldiazo compounds with selenosulfonates, providing various γ-seleno allylic sulfones in good yields. This photochemical reaction was carried out at room temperature in an open flask using ethyl acetate as the solvent without any photocatalysts or additives. The control experiments corroborated that the 1,3-addition proceeded via a radical-chain propagation process. The synthetic applications of the resulting products were demonstrated by deselenization, reduction, bromination and allylation.
N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack adducts with 1,3,5-triazine compounds as efficient catalysts for the transesterification of β-ketoesters
Chityala, Yadaiah,Duguta, Govardhan,Kamatala, Chinna Rajanna,Muddam, Bhooshan,Mukka, Satish Kumar
supporting information, p. 1641 - 1655 (2020/05/25)
N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack (VH) adducts with 1,3,5-triazine compunds such as trichloroisocyanuric acid (TCCA) and trichlorotriazine (TCTA) were prepared by replacing classical oxy chlorides POCl3, and SOCl2, which were explored as efficient catalysts for the transesterification of β-ketoesters. The prepared (TCCA/DMF) and (TCTA/DMF) adducts improved greenery of the classical Vilsmeier–Haack reagents (POCl3/DMF), and (SOCl2/DMF), and demonstrated their better efficient catalytic ativity. Reaction times were in the range: 3.5 to 6.5 hr (SOCl2/DMF); 2.8–5.2 hr (POCl3/DMF); 2.5–5.2 hr (TCCA/DMF) and 2.5–5.0 hr (TCTA/DMF) catalytic systems. Ultrasonically (US) assisted protocols with these reagents further reduced the reaction times (two to three times), while microwave assisted (MW) protocols with these reagents were much more effective. The reactions could be completed in only few seconds (less than a minute) in MWassisted protocols as compared to US assited reactions, followed by good product yields.
