Organocatalytic Enantioselective Selenosulfonylation of a C–C Double Bond To Form Two Stereogenic Centers in an Aqueous Medium

Abstract

Organocatalytic selenosulfonylation of the C–C double bond of α,β-unsaturated ketones to construct two contiguous stereogenic centers in an aqueous medium was described. A series of α-selenyl and β-sulfonyl ketones with various functional groups were synthesized in good yields and enantioselectivities with saturated NaCl solution as the solvent. In addition, this protocol had been successfully scaled up to a decagram scale via a simple workup procedure.

Synthesis and NLRP3-Inflammasome Inhibitory Activity of the Naturally Occurring Velutone F and of Its Non-Natural Regioisomeric Chalconoids

“…Initially, we planned a synthetic strategy to compound 1 based on the introduction of the required alkene by Wittig olefination of 5-formyl-4,7-dimethoxy benzofuran 7 ( 5-FBF ) with the 1-phenyl-2-(triphenylphosphoranylidene)ethanone counterpart 8 [ 35 ]. To this end we elaborated two synthetic approaches for the preparation of the key intermediate 5-FBF differing in the way the benzofuran core ( BF ) could be formed via annellation of the carbocyclic ring system onto a preformed furan, synthetic pathway A ( Scheme 1 ), or alternatively, by creating the furan ring by intramolecular cyclization on a preexistent carbocyclic, synthetic pathway B ( Scheme 2 ).…”

“…Subsequently, the methoxycarbonyl group was converted to the required formyl group by a two-step process entailing reduction with LiAlH 4 and oxidation of the resulting primary alcohol with pyridinium chlorochromate (PCC). The resulting 5-FBF was eventually reacted with the stabilized phosphorous ylide 8 , in turn, prepared according to the literature [ 35 ]. The Wittig olefination under microwave irradiation provided velutone F ( 1 ) in 70% yield after chromatographic purification.…”

Direct selenosulfonylation of unsaturated compounds: a review

“…Subsequently, Mao and Qin elegantly solved this limitation by performing the process in saturated NaCl solution, which afforded the expected a-selenyl b-sulfonyl ketone derivatives with two contiguous stereogenic centers in decent yields. 32 In a signicant contribution in this research arena, Sun and Zhang along with their co-workers developed an efficient threecomponent synthesis of b-phenylselenosulfones 17 from terminal alkenes 14, arylsulfonyl hydrazides 15 and diaryl diselenides 16 under catalyst-free conditions (Scheme 7). 33 By employing styrene, 4-methyl benzene sulfonyl hydrazine, and diphenyl diselenide as the model reactants, several oxidants such as (NH 4 ) 2 S 2 O 8 , K 2 S 2 O 8 , ozone, and tert-butyl hydroperoxide (TBHP) were carefully screened.…”

Electrophilic Thiocyanato Reagent Assisted Oxa-Michael/Thiocyanation of α,β-Unsaturated Ketones

“…Substrates 1a and 1b are commercially available. Substrates 1c – 1k , , 3a , 3b and 3c , 3d and 3e , 3f , 3g – 3q and 3s and 8 , , and 5a and 5b are known compounds and prepared according to known procedures.…”