Simple propargylic silyl ethers can be converted to complex cyclopropylboronic acid pinacol esters in an efficient one-pot procedure. Terminal acetylenes undergo a Schwartz's reagent catalyzed hydroboration; subsequent addition of further Schwartz's reagent and Lewis acid-mediated activation of neighboring silyl ether allows cyclization to access a range of cyclopropylboronic acid pinacol esters. The scope includes aromatic, aliphatic, quaternary, and spiro substituted cyclopropyl rings, which can be transformed via Suzuki coupling into a range of lead-like substituted cyclopropyl aryl products.
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http://dx.doi.org/10.1021/acs.orglett.7b01778 | DOI Listing |
Chem Commun (Camb)
December 2022
Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India.
Organoboron compounds have a wide-range of applications in synthetic methodologies, natural products, and bioactive molecule synthesis. The sensitivity of boronic acid toward most synthetic reagents makes it necessary to introduce a protecting group before its utilization. Benchtop stable MIDA boronates have been found compatible with various common synthetic reagents which opens the doors for the synthesis of various small building blocks, natural products, and bioactive compounds.
View Article and Find Full Text PDFInsect Biochem Mol Biol
January 2022
Entomology Department, School of Natural Resource Management, North Dakota State University, PO Box 6050, Fargo, ND, 58108-6050, USA. Electronic address:
Many species of moths have a common control mechanism for synthesizing sex pheromone: the circadian release of pheromone biosynthesis-activation neuropeptide (PBAN) that switches pheromone synthesis on/off during the day. One apparent exception to this is the noctuid moth Trichoplusia ni (Hübner), in which pheromone synthesis appears continuous through the photoperiod, with circadian release of PBAN controlling emission rate of pheromone during calling. Sex pheromone biosynthesis was reinvestigated in T.
View Article and Find Full Text PDFBeilstein J Org Chem
May 2019
Département de chimie, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal, Québec, H3C 3P8, Canada.
The copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid is reported. The procedure operates under simple conditions to afford the corresponding aryl cyclopropyl sulfides in moderate to excellent yields. The reaction tolerates substitution in , and -substitution as well as electron-donating and electron-withdrawing groups.
View Article and Find Full Text PDFOrg Lett
July 2017
GlaxoSmithKline, Gunnels Wood Road, Stevenage, Herts SG1 2NY, U.K.
Simple propargylic silyl ethers can be converted to complex cyclopropylboronic acid pinacol esters in an efficient one-pot procedure. Terminal acetylenes undergo a Schwartz's reagent catalyzed hydroboration; subsequent addition of further Schwartz's reagent and Lewis acid-mediated activation of neighboring silyl ether allows cyclization to access a range of cyclopropylboronic acid pinacol esters. The scope includes aromatic, aliphatic, quaternary, and spiro substituted cyclopropyl rings, which can be transformed via Suzuki coupling into a range of lead-like substituted cyclopropyl aryl products.
View Article and Find Full Text PDFJ Am Chem Soc
June 2015
Laboratoire de Synthèse Organique, CNRS UMR 7652, Ecole Polytechnique, 91128 Palaiseau Cedex, France.
The inability of the sp(3) boron in MIDA boronates to stabilize an adjacent radical makes possible the efficient addition of a wide array of xanthates to vinyl MIDA boronate, leading to highly functionalized and diverse aliphatic organoboron structures. The lack of radical stabilization also allows the exchange of the xanthate in the adducts with a bromine. In one case, the bromine was substituted to generate a cyclopropyl MIDA derivative.
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