Stereoselective allylic transposition by means of allylic n-pentenyl ethers. Part 2: Synthesis of nitrogen heterocycles

A Concise Synthesis of (–)‐ and (+)‐trans‐Whisky Lactones

“…Thus, none of the following reagents gave the desired trans-4-methyl-5-(1-butenyl)-γ-butyrolactone in an acceptable yield: Pd/C-H 2 , tBuLi, [20] TTMSS, [21] and Pd(PPh 3 ) 4 -HCO 2 NH 4 . Thus, we turned our attention to dehydroiodination.…”

Facile and Efficient Synthesis of Lactols by a Domino Reaction of 2,3‐Epoxy Alcohols with a Hypervalent Iodine(III) Reagent and Its Application to the Synthesis of Lactones and the Asymmetric Synthesis of (+)‐Tanikolide

“…Although the catalytic hydrogenation of (+)-24 with a Pd/C catalyst without quinoline gave a complex mixture (Table 6, entry 3), the iodine atom was reduced in the best yield by catalytic hydrogenation with the Pd/C catalyst in the presence of quinoline (Table 6, entry 4). [19] These conditions were then used for the conversion of the iodoolefin alcohol (+)-24 into the allyl alcohol (+)-22. The obtained (+)-22 was found to have an ee value of 98 %.…”

“…The combined organic layer was washed with brine, dried over Na 2 SO 4 , and evaporated in vacuo. After the residue had been filtered through a pad of silica gel with hexane/ [19] quinoline, AcONa EtOH RT 96…”

“…[15] After the resulting mixture had been stirred for a further 30 min, MeOH was added and the solvent was removed in vacuo. By catalytic hydrogenation in the presence of quinoline: [19] 10 % Pd/C (120 mg) was added to a solution of (+)-24 (454 mg, 1.2 mmol), sodium acetate, and quinoline (catalytic amount) in MeOH (120 mL). After being stirred under a H 2 atmosphere (1 atm) for 1 h, the reaction mixture was filtered through a pad of Celite.…”

Acetylenosaccharides

“…Although additions to pyranoses have also been described (see, for example, [60,120,121]), the ring-closing reaction has only been used for the preparation of glycofuranosylacetylenes. The glucopyranosyl hydroxylamine 75 was transformed via the tautomeric hydroxynitrone into the propargylic hydroxylamines 76a and 76b [122], and the 2-hydroxypyrrolidine 77 was selectively converted into the hydroxy tosylamide 78 [123]. …”