10.1002/1615-4169(200108)343:6/7<618::AID-ADSC618>3.0.CO;2-E
The research focuses on the synthesis of both enantiomers of levoglucosenone from acrolein dimer using lipase-mediated kinetic hydrolysis. The purpose of this study was to develop an efficient method for the synthesis of levoglucosenone, a chiral building block with high chemical potential, which is utilized in the construction of various optically active compounds. The researchers concluded that they had successfully developed a new route to racemic levoglucosenone and its resolution into both enantiomers of enantiopure levoglucosenone. Key chemicals used in the process included acrolein dimer, sodium borohydride, vinyl acetate, p-toluenesulfonic acid, m-chloroperbenzoic acid, o-iodoxybenzoic acid, and various lipases for the enzymatic resolution steps. The synthesis involved several steps, including reduction, oxidative acetalization, Swern oxidation, and dehydrogenation, ultimately leading to the desired enantiomers of levoglucosenone.
10.1248/cpb.48.1833
The research describes the first total synthesis of mytiloxanthin 2, a compound with a unique cyclopentyl enolic β-diketone group conjugated to the polyene chain. The purpose of this study was to achieve the biomimetic total synthesis of mytiloxanthin 2 using a stereoselective rearrangement of epoxides. Important reagents include p-methoxybenzyloxymethyl (PMBM) chloride for protection, LiAlH? for reduction, o-iodoxybenzoic acid (IBX) for oxidation, and vinyl bromide 13 for the introduction of the C10-unit. The synthesis involved several steps, including the reduction of ketone 7 to obtain compound 11, conversion to aldehyde 12, and subsequent oxidation to yield ketone 14. The final steps involved the protection of the diketone moiety with an acetyl group to form acetate 17, partial deprotection with tetrabutylammonium fluoride (TBAF), oxidation with IBX, and final deprotection with HF to obtain the cis-β-diketone-aldehyde 8b. The cis-aldehyde 8b was then reacted with the C10-phosphonium salt 19 in the presence of KOH to form an isomeric mixture, which was condensed with the acetylenic Wittig salt 20 to yield mytiloxanthin 2. The spectral data of the synthesized mytiloxanthin 2 were in good agreement with those of a natural specimen, confirming the successful total synthesis.
10.1021/jo801580g
The study, titled "Oxidative Conversion of r,r-Disubstituted Acetamides to Corresponding One-Carbon-Shorter Ketones Using Hypervalent Iodine (λ5) Reagents in Combination with Tetraethylammonium Bromide," investigates a novel method for converting R,R-disubstituted acetamides into ketones that are one carbon atom shorter. The key chemicals involved are hypervalent iodine (λ5) reagents, specifically o-iodoxybenzoic acid (IBX) and Dess-Martin periodinane (DMP), and tetraethylammonium bromide (TEAB). These reagents are used to oxidatively dehomologate R,R-disubstituted acetamides, resulting in the formation of ketones. The study establishes a mild, efficient, and general method for this transformation, with IBX and TEAB in acetonitrile at 60 °C yielding the best results. The researchers also explored the reaction mechanism, proposing that an N-bromoimine intermediate forms during the process, which subsequently hydrolyzes to produce the ketone.
C, 
Xi, 
Xn
