Sulphonate esters as sources of sulphonyl radicals; ring-closure reactions of alk-4- and -5-enesulphonyl radicals

Synthesis, Structure, and Unusual Reactivity of a Stable 3-(Oxazolidin-2-ylidene)thiophen-2-one

“…Bis­(trimethylsilyl)­peroxide, benzyl methanesulfonate, 4-phenyl-1,2,4-triazoline-3,5-dione, and tetrachlorothiophene S,S -dioxide were prepared by published methods. Thiophene-3-carboxylic acid was prepared by Ag 2 O oxidation of thiophene-3-carbaldehyde .…”

Novel Convenient Approach to 6-, 7-, and 8-Numbered Nitrogen Heterocycles Incorporating Endocyclic Sulfonamide Fragment

“…Much to our surprise, this methodology was never applied to unsaturated compounds with double or triple carbon-carbon bond as nucleophilic site and sulfonyl chloride as electrophile. Although intermolecular addition of sulfonyl chlorides to olefins under free-radical conditions (atom transfer radical addition) is well documented and widely used for the preparation of α-chloro sulfones and vinyl sulfones (see e.g., [ 25 , 26 , 27 , 28 , 29 ] and references therein), there is only one publication reporting small-scale homolytic intramolecular heterocyclization of pent-4-sulfonyl chloride proceeding at high temperature (AIBN-CuCl 2 , MeCN, 170 °C) and resulting in 3-chlorotetrahydrothiopyran 1,1-dioxide in a low yield (17%) [ 30 ]. Obviously, this heterocyclization is of low preparative value and has rather theoretical meaning.…”

“…Alternative direction involving cyclization on terminal carbon atom of the C=C bond (route b) was not observed. It is worth of noting that Cu catalyzed photoredox chlorosulfonation of terminal alkenes and alkynes proceeds in accordance with path b, i.e., the addition of the sulfonyl group occurs on the terminal carbon atom [ 30 ].…”

“…It should be noted that, to the best of our knowledge, there has been no example of sulfonyl group addition to the non-terminal carbon atom of monosubstituted alkynes. Reported in the literature copper [ 30 ], iron [ 31 ], and iridium [ 32 , 33 ] catalyzed radical sulfonation of alkynes with sulfonyl chlorides takes place at the terminal carbon atom. Regiospecific intramolecular addition to the non-terminal atom of alkyne 20 in Scheme 7 results most likely from beneficial six-member ring formation.…”

Development, Scope, and Mechanism of the Palladium‐Catalyzed Intramolecular Hydroalkylation of 3‐Butenyl β‐Diketones.

“…[7] 3-Methyl-7-octene-2,4-dione (Table 2, entry 5) [8] and (E)-2,3-dibromo-1-phenylsulfonylpropene [9] were prepared according to the published procedures.3,3-Dideuterioallyl methanesulfonate (S1) was prepared from 3,3-dideuterio-2-propene-1-ol [10] employing a procedure analogous to that used to synthesize unlabeled allyl methanesulfonate. [11] (Z)-3-Bromo-1,2dideuteriopropene (S2) and 3-bromo-3,3-dideuterio-1-propene (S3) were synthesized from reaction of (Z)-2,3-dideuterio-2-propene-1-ol [12] and 1,1-dideuterio-2-propene-1-ol, [13] respectively, with…”