ABSTRACT
Stereochemical evidence is presented to demonstrate that (-)-inthomycin C has (3R)- and not (3S)-stereochemistry. Careful reappraisal of the previously published work2-5 now indicates that the Hatakeyama, Hale, Ryu, and Taylor teams all have synthesized (-)-(3R)-inthomycin C. The newly measured [α]D of pure (-)-(3R)-inthomycin C (98% ee) is -7.9 (c 0.33, CHCl3) and not -41.5 (c 0.1, CHCl3) as was previously reported in 2012.
Subject(s)
Oxazoles/chemistry , Molecular Structure , StereoisomerismABSTRACT
A novel formal [4 + 1]-cycloaddition of readily available homopropargyl alcohols with diazo dicarbonyl compounds is described, which involves tandem O-H insertion/Conia-ene cyclization under cooperative Rh(II)/Zn(II) catalysis. This reaction provides easy access to various substituted tetrahydrofurans and exhibits complete E-selectivity in the case of nonterminal alkynes.
Subject(s)
Alcohols/chemistry , Azo Compounds/chemical synthesis , Furans/chemistry , Pargyline/analogs & derivatives , Pargyline/chemistry , Azo Compounds/chemistry , Catalysis , Cycloaddition Reaction , Molecular StructureABSTRACT
Complementary chemistry! α-Isocupreine (-ICPN) was synthesized for the first time in one step from quinine by treatment with CF3SO3H (see scheme). This compound serves as an enantiocomplementary catalyst to ß-isocupreidine (ß-ICD) in the MoritaBaylisHillman reaction.
Subject(s)
Hydroxyquinolines/chemistry , Quinuclidines/chemistry , Aldehydes/chemistry , Catalysis , Crystallography, X-Ray , Molecular Conformation , Quinine/chemistry , StereoisomerismABSTRACT
The stereocontrolled total synthesis of (-)-cinatrin C1, a phospholipase A2 inhibitor, has been accomplished. The key feature includes the stereoselective construction of the highly substituted tetrahydrofuran core by In(OTf)3-catalyzed Conia-ene reaction of the oxygen-tethered acetylenic malonic ester followed by dihydroxylation with concomitant lactonization.