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Syntheses of 9-vinylated Benzotropolones by a Sequence of Acylation, Ring-closing Enyne Metathesis, and Oxidation

Sarah N. MommChristian SeifriedReinhard Brückner

出版	Universität, 2023
URL	http://books.google.com.hk/books?id=DFZg0AEACAAJ&hl=&source=gbs_api

註釋Abstract: Previous studies from our group revealed that 6,7-benzannulated nona-1,8-diene-5-ones of a variety of substitution patterns undergo ring-closing diene metatheses in the presence of the Grubbs-II catalyst; the benzocycloheptadienones formed thereby gave benzotropolones in between one and four follow-up steps. The present study discloses that exemplary 6,7-benzannulated non-1-en-8-yn-5-ones undergo ring-closing enyne metatheses in the presence of the Grubbs-II catalyst; the vinylated benzocycloheptadienones formed thereby gave 9-vinylbenzotropolones in four steps: silyl enol ether formation, Rubottom-type oxidation, desilylation, and Dess-Martin oxidation. The metathesis substrates were synthesized either from (ortho-bromoaryl)ethynes with an unsubstituted sp-carbon by a Br→Li exchange and an acylation with an H2C=CH-containing Weinreb amide; or, they were synthesized from (ortho-bromoaryl)ethynes with a trimethylsilylated sp-carbon by a Br→Li→ZnHal exchange, an acylation with an H2C=CH-containing thioester, and a desilylation