The effect of sulfoxides on the stereoselective construction of tetrahydrofurans: total synthesis of (+)-goniothalesdiol.
Good to excellent stereoselectivities were achieved in the reductive cyclization (with Et(3)SiH/trimethylsilyl trifluoromethanesulfonate (TMSOTf)) of enantiopure hydroxy sulfinyl ketones en route to 2,5-cis-disubstituted tetrahydrofuran skeletons. Electrostatic effects of the exocyclic sulfoxide, which stabilized the reactive intermediate oxocarbenium conformations, were responsible for the observed stereocontrol. A model is proposed to explain the results. The use of this reaction and the asymmetric β-ketosulfoxide reduction as key steps facilitated the total enantioselective synthesis of the natural β-C-aryl glycoside (+)-goniothalesdiol.
Departamento de Química Orgánica (Módulo 01), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Gloria
G
Hernández-Torres
M Carmen
MC
Carreño
Antonio
A
Urbano
Françoise
F
Colobert
D001688:Biological Products / Q000737:chemistry*; D003500:Cyclization; D005663:Furans / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism; D013454:Sulfoxides / Q000737:chemistry*
D001688:Biological Products; D005663:Furans; D013454:Sulfoxides; C512388:goniothalesdiol; C030011:carbene; D008697:Methane