New developments of thiocarbonyl compounds and sulfines in organic synthesis

Abstract

The oxidation reaction of aliphatic thiocarbonyl compounds has been revisited in order to give access to the elusive corresponding suljines and to achieve thiophilic addition of nucleophiles. Various compounds (thioketones, dithioesters, thionesters, trithiocarbonates, trithioperesters) an addition reaction and not by deprotonation). A second illustration of the specijic properties of sulfur compounds is disclosed with a new asymmetric version of the Claisen rearrangement. Sulfur is used to facilitate the thermal course of the reaction and a sulfinyl adjacent group is introduced for diastereocontrol First examples show that this transposition indeed occurs at room temperature and with an excellent diastereomeric ratio (2 93:7).Sulfur plays a major role in heteroatom chemistry (1). We wish to report our recent results showing more applications to organic synthesis for the specific properties of some sulfur groups. Replacement of the oxygen of a carbonyl group by a sulfinyl group (using a sulfine) allows to reverse the polarity of the C=S moiety and the attack of a nucleophile takes place on sulfur rather than on carbon. TMoDhiIlc addNonA second part will focus on the replacement of oxygen by sulfur to facilitate a Claisen rearrangement. It is also shown, for the first time, that an auxiliaiy sulfinyl group can be used efficiently for the diastereocontrol of this [3.3] sigmatropic shift in the acyclic series. New SulfinesSulfines are attractive heterocumulenes (2, 3) whose synthesis and reactivity have been studied with success by Zwanenburg and co-workers, and by the groups of Bonini-Mazzanti (4) and Block (5). Some years ago we embarked on revisiting the oxidation reaction of aliphatic thiocarbonyl compounds (6). For some time we had been puzzled by the literature reports (2,7,8) assuming that enethiolizable thiocarbonyl compounds would not react with oxidizing agents to yield sulfines but would rather lead to divinyl disulfides through oxidation of the tautomeric enethiols. 863

First Use of Axially Chiral Thioamides for the Stereocontrol of C−C Bond Formation

“…On the other hand, the rearrangement step took place readily, stressing once again its relatively facile nature in the sulfur series. [24,51,52] Thus, in a number of cases, yields around 80 % were obtained for unsaturated thioamides 4.…”

Synthesis and morphological characterization of block copolymers for improved biomaterials

“…Based on these reports the synthesized block copolymers could also be transformed into a range of useful compounds as it incorporates terminal thiocarbonylthio groups for further modifications. In addition, the synthesized block copolymers 5a–c could also be further modified to well-defined end functional block copolymers [44–45]. …”

Synthesis of Novel Trithiocarbonate-S-Oxides

“…The 13 C NMR signal of the >C S group of 3 resonates at 224 ppm for 3a and at 216.53 ppm for 3b lower field shift compared with the starting chlorodithioformates 1 which resonate at 198.10 for 1a and 189.50 ppm for 1b respectively.…”