Asymmetric alpha-alkynylation of piperidine via N-sulfinyliminium salts.
Piperidine was stereoselectively alpha-alkynylated in a four-step sequence made up of transformation to a chiral nonracemic N-sulfinylpiperidine, anodic oxidation to N-sulfinyliminium ion equivalent, alkynylation through addition of a mixed organoaluminum derivative, and final acidic deprotection of the sulfoxide. Overall yields are around 50%, and the diastereoselectivity of the nucleophilc addition was between 92 and 99% de, allowing isolation of the final product with 99% enantiomeric purity.
Turcaud
Serge
S
Synthèse et Structure de Molécules d'Intérêt Pharmacologique, UMR 8638 CNRS-Université Paris 5, 75270 Paris cedex 6, France.
Sierecki
Emma
E
Martens
Thierry
T
Royer
Jacques
J
D000480:Alkynes / Q000737:chemistry*; D017607:Aluminum Compounds / Q000737:chemistry; D007097:Imines / Q000737:chemistry*; D008745:Methylation; D015394:Molecular Structure; D010880:Piperidines / Q000138:chemical synthesis / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D013237:Stereoisomerism; D013455:Sulfur / Q000737:chemistry*
D000480:Alkynes; D017607:Aluminum Compounds; D007097:Imines; D010880:Piperidines; D012492:Salts; C032727:piperidine; D013455:Sulfur