Construction of thiazines and oxathianes via [3 + 3] annulation of N-tosylaziridinedicarboxylates and oxiranes with 1,4-dithiane-2,5-diol: application towards the synthesis of bioactive molecules

Abstract

Lewis acid catalyzed [3 + 3] annulation of N-tosylaziridinedicarboxylates and oxiranes with in situ generated mercaptoaldehyde for the synthesis of functionalized thiazine and oxathiane derivatives has been developed. Additionally, this method facilitates the derivatization of thiazines by detosylation and Krapcho monodecarboxylation.

Domino Processes of Arynes Reacting with Three Classes of Nucleophiles for Organic Syntheses

“…The residue was purified by use of column chromatography (5.0 % EtOAc in hexanes as the eluent) to give epoxide 16 (39.3 mg, 0.148 mmol) in 80 % yield as a colorless oil: TLC R f =0.40 (5.0 % EtOAc in hexanes as the eluent); 1 H NMR (CDCl 3 , 400 MHz) δ 7.32–7.28 (m, 2 H, 2×ArH), 7.25–7.19 (m, 3 H, 3×ArH), 4.54 (s, 1 H, CHPh), 4.33–4.28 (m, 2 H, OCH 2 ), 4.04–3.98 (m, 2 H, OCH 2 ), 1.31 (t, J =7.2 Hz, CH 3 ), 0.94 (t, J =7.2 Hz, CH 3 ). These spectroscopic data are in accordance with the literature values [52] …”

“…These spectroscopic data are in accordance with the literature values. [52] 1-Allyl-2-methoxybenzene (18 a). The Standard Procedure 3 was followed by use of 2-silylphenyl triflate 1 a (302 mg, 1.01 mmol, 1.0 equiv), 3-methoxy-1-propene (17 a, 146 mg, 2.02 mmol, 2.0 equiv), and CsF (184 mg, 1.21 mmol, 1.2 equiv) in THF (3.5 mL).…”

Metal-free anomalous [5+1] cycloaddition reactions of donor–acceptor aziridines for the synthesis of 2H-1,4-oxazines

“…Donor–acceptor aziridines are versatile building blocks for the construction of nitrogen-containing biologically active compounds. 19 Their intrinsic high ring strain renders them susceptible to undergo typical C–C bond heterolytic cleavage to generate active azomethine ylides in the presence of a Lewis acid, thus participating in [3+1], 20 [3+2], 21 and [3+3] 22 cycloaddition reactions with various dipolarophiles. In these reactions, an active transient azomethine ylide intermediate was used as a masked 1,3-dipole.…”

Lewis Acid‐Catalyzed Intramolecular [3 + 2] Cross‐Cycloaddition of Donor‐ Acceptor Epoxides with Alkenes for Construction of Oxa‐[n.2.1] Skeletons

“…Among such epoxides, those being activated by two geminal electron-withdrawing groups, can be named as GDA-epoxides (geminally double acceptors expoxides) and have received great attention recently. While thermal [3] or Lewis-acids (LAs) [4,5] intermolecular [3+2] cycloadditions of GDA-epoxides with various dipolarophiles have been widely studied, their intramolecular versions have seldom been investigated. [3d,3e,3h,3j,3k,6,7] [3+2]IMCC of donor-acceptor epoxides with carbon-carbon double bonds was seldom investigated, [8] and to the best of our knowledge, there're no LA-catalyzed intramolecular [3+2] cycloadditions of GDA-epoxides with carbon-carbon double bonds reported yet.…”