Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• additive-free synthesis of 2-benzyl N-substituted anilines from (E)-2-arylidene-3-cyclohexenones and primary amines has been reported. The reaction proceeds smoothly through a sequential imine condensation–isoaromatization pathway, affording a series of synthetically useful aniline derivatives in

• acceptable to high yields. Mild reaction conditions, no requirement of metal catalysts, operational simplicity and the potential for scale-up production are some of the highlighted advantages of this transformation. Keywords: aniline; (E)-2-arylidene-3-cyclohexenone; imine condensation; isoaromatization

• -substituted anilines from (E)-2-arylidene-3-cyclohexenones and primary aliphatic amines. The reaction proceeds through an imine condensation–isoaromatization approach under catalyst- and additive-free conditions, allowing the generation of synthetically useful aniline derivatives in 23–82% yields. This method

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• reaction (Scheme 6). The increased amount of the condensation agent T3P® obviously enables further activation of the initially formed 1H-benzo[f]isoindole-1,3(2H)-dione by electrophilic attack on the sterically easier accessible carbonyl group. As a consequence the imine condensation proceeds also with

• sterically more biased carbonyl group (Scheme 7). In addition to NMR spectroscopic and mass spectrometric characterization the crystal structures of the imine condensation products 5 and 6 were determined (Figure 2 and Figure 3) [50]. In similarity to 4b the twist angles of the phenyl substituents (rings A

• slightly hypsochromically (Table 6, entries 1, and 3–6) the electron-donating methoxy group (Table 6, entry 2) clearly causes a red shift. The absorption spectra of the imine condensation products 5 and 6 essentially display a similar appearance; however, the pentacycle 6 possesses a considerably more

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• ]. Two successive SET’s from the alcohol to the photoexcited TiO2 catalyst, and subsequent proton loss, brought about conversion to the corresponding aldehyde. Imine condensation with the amine ensued, followed by reduction–protonation yielding the coupled product 20. The reaction occurred readily in the

Diastereoselectivity in the Staudinger reaction of pentafluorosulfanylaldimines and ketimines

• Alexander Penger,
• Cortney N. von Hahmann,
• Alexander S. Filatov and
• John T. Welch

Beilstein J. Org. Chem. 2013, 9, 2675–2680, doi:10.3762/bjoc.9.303

• consistent with retardation the rate of E/Z imine isomerization by the electron withdrawing pentafluorosulfanyl group [35]. In the reaction of 12, the E/Z ratio of the imine was reflected very well in the 1,2-diastereomeric excess of the product β-lactam 7e . The ketene–imine condensation of 7c is influenced