Direct Organocatalytic α-Sulfenylation of Aldehydes and Ketones with Tetramethylthiuram Disulfide

Abstract

The direct pyrrolidine-catalyzed a-sulfenylation of aldehydes and ketones with the commercially available, very cheap chemical tetramethylthiuram disulfide (thiram) is described. The dithiocarbamoyl derivatives are obtained in good to excellent yields (47-98%). In the case of a-substituted aldehydes the protocol allows the generation of quaternary stereocenters. The sensibility of the a-sulfenylated carbonyl compounds for racemization has been investigated.

Disulfide-based metal-free α-sulfanylation of ketones

“…To our knowledge, there are just few examples of direct catalytic a-sulfanylation of unmodied carbonyl compounds which are based on the use of N-(phenylthio)phthalimide 6b or sulfonyl chloride derivatives 6 but excluding the interesting results obtained by Enders and co-workers using tetramethylthiuram disulde, 11 no examples of organocatalyzed reactions involving diaryldisuldes as reagents have been reported to date. In this paper we now wish to report the development of a new proline-catalyzed ketosulde synthesis from aryldi-suldes and ketones.…”

“…As expectable, analogous results in terms of yields and reaction times were achieved with those observed for D,L-proline but unluckily, HPLC analysis of the isolated cyclobutanone 2a showed the formation of a racemate. 11 Reactions employing other chiral not racemic pyrrolidine-catalysts (see ESI †), were also inefficient in terms of asymmetric induction. We believe that this result can be rationalized by taking in consideration, the reduced formation of a stable hydrogen-bonding interaction between the disulde and the transient enamine-adduct due to the operation high temperatures.…”

Transition‐Metal‐Free C(sp3)–S Coupling in Water: Synthesis of Benzyl Dithiocarbamates Using Thiuram Disulfides as an Organosulfur Source

“…Thus, different bases were screened and K 2 CO 3 was chosen as the best one (entries [6][7][8]. As for benzyl bromides, substituents ranging from weak electron-withdrawing groups, such as Br and methyl ester, to strong electronwithdrawing groups, such as NO 2 , along with electron-donating methoxyl groups, all furnished the desired benzyl diethyldithiocarbamates in good yields (entries [15][16][17][18][19][20]. The optimal reaction conditions were summarized in entry 9 and the subsequent control experiments (entries [11][12] revealed that 100°C was the most suitable temperature for benzyl bromide.…”

“…[8][9][10][11] Some methods for their synthesis involve the reaction of benzyl alcohols and dithiocarbamates. [15,16] However, these methods require using large amounts of organic solvents, toxic and foul smelling reagents, or organometallic reagents sensitivity to air and moisture, which limit their application in pharmaceutical synthesis. [15,16] However, these methods require using large amounts of organic solvents, toxic and foul smelling reagents, or organometallic reagents sensitivity to air and moisture, which limit their application in pharmaceutical synthesis.…”

An Efficient Copper-Catalyzed C(sp2)–S Formation Starting from Aryl Iodides and Tetramethylthiuram Monosulfide (TMTM)

“…1 As a result, thiuram reagents have achieved multifield applications as vulcanization promoters, animal repellents, and antifungal agents. 2 Among these, sodium dialkyl dithiocarbamates are widely used in industrial compounds for downstream usage of medicines, 3 pesticides, 4 and vulcanization accelerators. 5 They can also be used as easily available sulfur reagents in synthetic chemistry.…”