A Sulfene Stable at −40 °C

Abstract

diameter afforded two fractions with specific optical rotations [a]:& = +4.3 and -2.5 O . After a second passage the rotations were [a]:& = +7.5 ' and -5 '' (1 % in CHCI3).

Trapping reactions of sulfenes generated from sulfonic acid derivatives and bases, 1. Cyclopentadiene, methylcyclopentadiene and 1,2,3,4‐tetraphenylcyclopentadiene used as sulfene scavengers. [4 + 2] cycloaddition reactions and sulfonylations

“…09, 7.42 and 124.7, 140.6, reflecting the double flanking of atom 8-H by the SO2 groups in 7-and 9-position. Moreover, the signal at 6 = 7.29 of 8a shows an additional 6J coupling with one of the CI-C5 1.382(10), C2-C3 1.435(10), C3-C4 1.360 (12), C4-C5 1.390(11), C1-S1 1.747 (7), C2-S2 1.710 (7), C4-S3 1.741(8); C2-Cl-C5 109.0(6), CI-C2-C3 105.8 (6), CI-C4-C5 107.7(7), C2-C3-C4 108.0(7), C3-C4-C5 109.6(7), C2-CI-Sl 129.4(5), C5-C1-Sl 121.7(6), CI-C2-S2 133.0(5), C3-C2-S2 120.9(6), C3-C4-S3 125.2 (6), C5-C4-S3 125.2(7), CI-SI-CIO 102.9(3), C2-S2-C20 104.7(4), C4-S3-C30 101.9(4). (2), S2-02B 1.445(1), S2-Cl 1.824(2), S2-C3 l.S55(2), Cl-C6 1.518 (3), CI-C7 1.533(3), C3-C4 1.560(3), C3-C9 1.521 (3), C4-C7 1.540(3), C4-C5 1.515(3), C5-C6 1.335(4); S2-Cl-C6 103.7(1), S2-CI-C7 100.2(1), S2-C3-C4 100.5( I), S2-C3-C9 119.3(1), Cl-S2-C3 93.8(1), CI-C7-C4 96.0(2), CI-C6-C5 106.5(2), C3-C4-C5 11 1.2(2), C6-Cl -C7 102.2(2), C3-C4-C7 103.1(2), C4-C3-C9 119.5 (2) H atoms in the 13-position.…”

“…This was clearly demonstrated by the reaction of mesyl chloride (Id) with Et3N and cyclopentadiene in MeCN at -40°C (Table 1 and Scheme 2). The sulfene 2d generated first is trapped by Et3N with formation of the labile sulfene-Et3N-SJ adduct 13d which, in turn traps further sulfene 2d to afford the more stable mesylsulfene-Et,N-S,Nadduct 14d [12]. The mesylsulfene (15d) presumed to be present in the equilibrium is now sufficiently reactive to furnish, by reaction with cyclopentadiene, the [4 -t 21 cycloadduct 6g (endofex0 = 1 : 1.2) in 80% yield.…”

Organic sulfur mechanisms. 19. Sulfene–tertiary amine zwitterions and base size effects in sulfene condensations

“…CH,=SO, + NMe, CH,SO,&M~, Presumably such zwitterions are involved also in the formation of the coupled zwitterions (3-5) first reported by Opitz et al (3) and which evidently lead to the further products described by Grossert (6,7). We report herein our efforts to see if such species are intermediates in other reactions as well.…”

Lewis Acid/Base Catalyzed [2+2]‐Cycloaddition of Sulfenes and Aldehydes: A Versatile Entry to Chiral Sulfonyl and Sulfinyl Derivatives

“…[15] 10 years later, King and Harding discovered that bsultone formation is improved by a large excess of a sterically nonhindered tertiary amine, such as NMe 3 . [16] This was attributed to the reversible formation of a reactive zwitterionic intermediate [17,5] from sulfenes and tertiary amines, which undergoes a cyclocondensation reaction with strongly polarized carbonyl groups.…”

“…Although their existence was spectroscopically demonstrated at low temperature, [4] they cannot be isolated due to rapid di-or oligomerization. [5,6] The use of sulfenes for asymmetric catalysis might offer a versatile synthetic access to scalemic sulfonyl derivatives. [7] Sulfonyl analogues of carbonyl derivatives are of increasing importance in medicinal chemistry, [8] because 1) they mimic the structural properties of tetrahedral intermediates, 2) they often provide high solubility in water, 3) they act as hydrogen-bond acceptors to interact, for example, with peptides, enzymes, or receptors, and 4) the SO 2 function can decrease the basicity of amino moieties in neighboring positions to a physiologically acceptable value.…”