ChemInform Abstract: Homochiral Fluoroorganic Compounds. Part 10. A New Protocol for the Synthesis of Variously Functionalized α‐Fluoroketones and α‐Fluoroalcohols.

Abstract

ChemInform Abstract Removal of the chiral sulfinyl group of (I) leads to the title ketones (II). Stereoselective reduction of (III) yields the corresponding alcohols with >95% d.e., which undergo desulfination to give the title alcohols (IV) with pure anti stereochemistry.

Stereoselective Synthesis of Monofluoroalkyl α,β-Unsaturated Ketones From Allenyl Carbinol Esters Mediated by Gold and Selectfluor

“…Monofluoroalkyl α,β-unsaturated ketones 1 are important molecular synthons, as showcased by their widespread use in the syntheses of bioactive compounds (Figure ) . Fluoroketone 1 is most commonly synthesized either by using a fluorine containing building block or through fluorination of an unsaturated ketone . But these methodologies have limitations.…”

Homochiral fluoroorganic compounds. Part 17. 2-(p-Tolylsulphinylmethyl)-3-fluorotetrahydro-pyrans and -furans through intramolecular oxymercuriation

“…Synthesis of' (3R)-and (3S)-3-Fluoro-6-methyl-1-[(R)-(ptolyl)suIphinyl]hept-5-en-2-one 2b.--In the same way starting from 1 -bromo-3-methylbut-2-ene (6.48 cm3, 56.04 mmol) a residue (10.0 g) was isolated which, after flash chromatography (hexane-ethyl acetate, 3:2) gave, in 1 : 1 ratio, as yellow pale liquids: compound (3R,Rs)-2b (4.74 g, 36%) (Found: C, 63.4; H, 6.8. C15H19FS02 requires C, 63.83; H, 6.74%); [a];' +182" (c 0.7, CHCI,); GH(CDC1,) 7.57 and 7.35 (4 H,m,ArH),5.03 (1 H, br t, J7.4, 5-H),4.72 (1 H, ddd, J49.0,6.3 and 5.0, 3-H),4.17 (1 H, dd, J 14.6 and 3.2, 1-Ha), 3.90 (1 H, dd, J 14.6 and 2.7, 1-Hb), 2.46 (2 H, m, 4-H,), 2.42 (3 H, br s, ArMe) and 1.67 and 1.56 (6 H, br s, 7-and 8-H3); compound (3S,RS)-2b (4.74 g, 36%) (Found: C, 63.5; H, 6.8%); [a]L' + 141" (c 0.4, CHCl,); G,(CDCl,) 7.57 and 7.34 (4 H, m, ArH), 5.1 1 (1 H, br t, J 7.4, 5-H), 4.71 (1 H, dt, J49.0 and 5.9,3-H), 4.04 (2 H, m, 1-H,), 2.52 (2 H, m, 4-H2), 2.42 (3 H, br s, ArMe) and 1.72 and 1.60 (6 H, br s, 7-and 8-H3).…”

“…89-90°C (from Et,O) (Found: C,63.3;H,7.3. C15H2,FS0,requires C,63.38;H,7.39%); [ L Y ] ~~ +97" (c 0.6, CHCl,); S,(CDCl,) 7.53 and 7.37 (4 H,m,ArH),5.05 (1 H,tqq,J 7.2,1.5 and 1.5,4.42 (1 H,dddd,J48.0,7.2,5.9 and 5.0, 3-H), 4.40(1 H,br,2-OH),4.17(1H,dddd,J11.8,9.5,5.9and1.9,2-H), 3.16 (1 H,ddd,J 13.7,9.5 and 0.7,2.83 (1 H,ddd,J 13.7,1.9 and 1.6,m,), 2.44 (3 H, br s, ArMe) and 1.67 and 1.57 (6 H, br s, 7-and 8-H3); GF(CDC13) o r ] ; ' + 155.4" (c 1.0, CHCl,). The diastereoisomeric ratios and the tRvalues were determined by HPLC (hexane-ethyl acetate, 1 :4); min; (2S,3S,5S,6R,Rs)-5, t R 6.82 min; (2S,3S,5S,7R,Rs)-4, t R 7.42 min.…”