Metal-catalyzed cycloetherification reactions of β,γ- and γ,δ-allendiols: chemo-, regio-, and stereocontrol in the synthesis of oxacycles.
Versatile routes that lead to a variety of functionalized enantiopure tetrahydrofurans, dihydropyrans, and tetrahydrooxepines are based on chemo-, regio-, and stereocontrolled metal-catalyzed oxycyclization reactions of β,γ- and γ,δ-allendiols, which were readily prepared from (R)-2,3-O-isopropylideneglyceraldehyde. The application of Pd(II), Pt(II), Au(III), or La(III) salts as the catalysts gives controlled access to differently sized oxacycles in enantiopure form. Usually, chemoselective cyclization reactions occurred exclusively by attack of the secondary hydroxy group (except for the oxybromination of phenyl β,γ-allenic diols 3b and 3d) to an allenic carbon atom. Regio- and stereocontrol issues are mainly influenced by the nature of the metal catalysts and substituents.
Alcaide
Benito
B
Grupo de Lactamas y Heterociclos Bioactivos, Departamento de Química Orgánica I, Unidad Asociada al CSIC, Facultad de Química, Universidad Complutense de Madrid, 28040 Madrid, Spain. alcaideb@quim.ucm.es
Almendros
Pedro
P
Carrascosa
Rocío
R
Martínez del Campo
Teresa
T
D000438:Alcohols / Q000737:chemistry*; D000466:Alkadienes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007811:Lanthanum / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D010082:Oxepins / Q000138:chemical synthesis* / Q000737:chemistry; D010165:Palladium / Q000737:chemistry; D010984:Platinum / Q000737:chemistry; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D012492:Salts; D013237:Stereoisomerism
D000438:Alcohols; D000466:Alkadienes; D005663:Furans; D008670:Metals; D010082:Oxepins; D011714:Pyrans; D012492:Salts; D010984:Platinum; C025947:propadiene; D010165:Palladium; D007811:Lanthanum; D006046:Gold