Rapid access to polyketide scaffolds via vinylogous Mukaiyama aldol reactions.
[reaction: see text]. The use of the Z-configured vinylogous silyl ketene acetals in Mukaiyama aldol reactions is described. Isopropyl alcohol as scavanger and the use of tris(pentafluorophenyl)borane as the Lewis acid are required for obtaining the gamma-alkylated syn-product selectively. In cases of alpha-chiral aldehydes, Felkin-Anh selectivity was observed.
Hassfeld
J
J
Institut für Organische Chemie der Universität Hannover, Schneiderberg 1B, D-30167 Hannover, Germany.
Christmann
M
M
Kalesse
M
M
D019840:2-Propanol; D000080:Acetals / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry; D001880:Boranes; D002384:Catalysis; D005030:Ethylenes / Q000737:chemistry*; D007202:Indicators and Reagents; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism
D000080:Acetals; D000447:Aldehydes; D001880:Boranes; D005030:Ethylenes; D007202:Indicators and Reagents; D007659:Ketones; C008223:ketene; D019840:2-Propanol