PMHS-mediated couplings of alkynes or benzothiazoles with various electrophiles: application to the synthesis of (-)-akolactone A.
Polymethylhydrosiloxane (PMHS) in combination with CsF facilitates the cross-coupling of alkynes or benzothiazoles with an array of vinyl, styryl, and aryl halides or nonaflates as well as acid chlorides. Experimental and spectroscopic evidence indicates that these reactions involve the in situ generation of a siloxyl intermediate. These cross-couplings proceed relatively quickly at room temperature and under amine-free conditions. To demonstrate the applicability of the method, a total synthesis of the cyctotoxic butanolide (-)-akolactone A was carried out.
Gallagher
William P
WP
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
Maleczka
Robert E
RE
D000480:Alkynes; D052160:Benzothiazoles; D002384:Catalysis; D007202:Indicators and Reagents; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D009005:Monosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry*; D013844:Thiazoles
D000480:Alkynes; D052160:Benzothiazoles; D007202:Indicators and Reagents; D007783:Lactones; D009005:Monosaccharides; D012833:Siloxanes; D013844:Thiazoles; C482354:carboxymethyl 3,4,6-tri-O-acetyl-alpha-D-glucopyranoside 2-O-lactone; C402373:poly(methylhydrosiloxane); C005465:benzothiazole