1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• Bram Ryckaert Ellen Demeyere Frederick Degroote Hilde Janssens Johan M. Winne Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 (S4), 9000 Gent, Belgium 10.3762/bjoc.19.12 Abstract This review covers the synthetic applications of 1,4-dithianes, as well as

• (hetero)aromatic building blocks. 1,4-Dithianes have as yet not been investigated to the same extent as their well-known 1,3-dithiane counterparts, but they do offer attractive transformations that can find good use in the assembly of a wide array of complex molecular architectures, ranging from lipids

• and carbohydrates to various carbocyclic scaffolds. This versatility arises from the possibility to chemoselectively cleave or reduce the sulfur-heterocycle to reveal a versatile C2-synthon. Keywords: 1,4-dithianes; 1,4-dithiins; 2,3-dihydro-1,4-dithiins; heterocycles; target synthesis; Introduction

Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study

• Michael L. McKee,
• Grzegorz Mlostoń,
• Katarzyna Urbaniak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44

• , with no exception, via a head-to-head dimerization yielding sterically crowded 1,4-dithianes of type 5 [9][10]. The analogous head-to-head dimerization course was reported for the thiocarbonyl S-methanide derived from benzyl octafluorodithiopentanoate [11]. The reaction mechanisms of the dimerization

Diradical reaction mechanisms in [3 + 2]-cycloadditions of hetaryl thioketones with alkyl- or trimethylsilyl-substituted diazomethanes

• Grzegorz Mlostoń,
• Paulina Pipiak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 716–724, doi:10.3762/bjoc.12.71

• ). When the decomposition of 2a or 2b was performed in the presence of a suitable dipolarophile, the corresponding [3 + 2]-cycloadducts were formed, whereas in the absence of a dipolarophile, the ‘head-to-head dimerization’ leading to 2,2,3,3-tetraaryl-1,4-dithianes 4a,b is the exclusive reaction

• . Only after warming up above −45/40 °C compounds 2 are expected to decompose yielding the reactive thiocarbonyl ylide 3. Under these conditions, the latter intermediates can undergo either 1,3-dipolar electrocyclization to give thiiranes 8 or dimerization leading to 1,4-dithianes 4 [20][26]. This

• ; anal. cald for C22H22S6Si (506.89): C, 52.13; H, 4.37; S, 37.96; found: C, 52.44; H, 4.55; S,37.71. ‘Head-to-head dimerization’ of diarylthioketone S-methanides 3a,b leading to 2,2,3,3-tetrasubstituted 1,4-dithianes 4a,b. Diradical nature of the reactive intermediate 3c in the reaction of phenyl