Tunable regioselectivity associated with the reaction of 2,3-dihalo-1-(phenylsulfonyl)-1-propenes with ambident nucleophilic reagents

2,3-Dihalo-1-(phenylsulfonyl)-1-propenes as versatile reagents for the synthesis of annulated furans and cyclopentenones

“…In the previous article, 2,3-dihalol-(phenylsulfonyl)-l-propenes were shown to react with a variety of heteronucleophiles and carbon nucleophiles to give substituted vinyl sulfones with predictable regiochemical control. 42 In the case of carbonyl enolate adducts, the sequence could be extended to furan formation via an O-alkylative ring closure. In practice, diactivated carbonyl compounds such as 5-diketones, /3-keto esters, and magnates are preferable to simple ketones for use as nucleophiles, since simple enolates induced decomposition of the 2,3-dihalo sulfones.…”

“…2-Állyl-3-[(phenylsulfonyl)methyl]-2-cyclopenten-l-one (42) . Using a procedure identical to that outlined for the synthesis of cyclopentenone 33, the reaction of 2.03 g of tert-butyl methylacetoacetate with 2.9 g of DBF gave 3.5 g (93%) of adduct 41 (R = allyl): IR (neat) 2936,1735,1710,1640 cm"1; -NMR (300 MHz, CDCI3) 1.49 (s, 9 H), 2.37 (s, 3 H), 2.75 (d, 2 H, J = 7 Hz), 4.30 (d, 1 H, J = 14 Hz), 4.73 (d, 1 H, J = 14 Hz), 5.07 (m, 2 ), 5.70 (m, 1 H), 6.48 (s, 1 H), 7.55 (m, 2 H), 7.63 (m, 1 H), and 7.92 (m, 2 H); 13C-NMR (75 MHz, CDC13) 27.9,28.2,41.9, 56.9,68.5,84.0,118.5,119.6,128.3,129.3,130.5,132.6,133.9,140.2, 168.1, and 202.2.…”

End game strategies towards the total synthesis of vibsanin E, 3-hydroxyvibsanin E, furanovibsanin A, and 3-O-methylfuranovibsanin A

“…For Padwa’s protocol the TMS enol ether 33 was required, which was obtained in 75% from sequential treatment of 30 with LDA and TMSCl. Subsequent reaction of 33 with Padwa’s electrophile 34 [ 24 ] and silver tetrafluoroborate gave a complex mixture with no identifiable trace of desired product 35 , a precusor to desired furan 36 ( Scheme 5 ). The lack of reactivity was without doubt substrate specific (i.e.…”

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

“…[2] Substrates 3, [3] 8-methyl-7-nonene-2,4-dione (Table 2, entry 11), [4] ethyl 3-oxo-6-heptenoate (Table 2, entry 12), [5] methyl 3-oxo-6-heptenoate (Table 2, entry 13) [6] and all new substrates were prepared from the appropriate 1,3-diketone or β-keto ester and allylic halide or tosylate employing a modified published procedure unless otherwise noted. [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…”

“…[2] Substrates 3, [3] 8-methyl-7-nonene-2,4-dione (Table 2, entry 11), [4] ethyl 3-oxo-6-heptenoate (Table 2, entry 12), [5] methyl 3-oxo-6-heptenoate (Table 2, entry 13) [6] and all new substrates were prepared from the appropriate 1,3-diketone or β-keto ester and allylic halide or tosylate employing a modified published procedure unless otherwise noted. [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.…”