Synthesis 2019; 51(20): 3834-3846
DOI: 10.1055/s-0037-1611896
paper
© Georg Thieme Verlag Stuttgart · New York

Enantioselective Synthesis of cis- and trans-Borocyclopropylmethanol: Simple Building Blocks To Access Heterocycle-Substituted Cyclopropylmethanols

Saher H. Siddiqui
,
Chandrasekhar Navuluri
,
FRQNT Centre in Green Chemistry and Catalysis, Department of Chemistry, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, Quebec, H3C 3J7, Canada   Email: andre.charette@umontreal.ca
› Author Affiliations
This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) (Discovery Grant DG-06438), the Canada Research Chairs program (227346), the Canada Foundation for Innovation (Leaders Opportunity Funds 227346), the Fonds de Recherche du Québec - Nature et Technologies (FRQNT Centre in Green Chemistry and Catalysis; RS-171310), and the Université de Montréal.
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Publication History

Received: 26 June 2019

Accepted: 02 July 2019

Publication Date:
01 August 2019 (online)


Abstract

An enantioselective and non-oxidative methodology was developed to obtain enantioenriched cyclopropyl boronates using a diethanolamine-promoted selective decomplexation of dioxaborolane. The non-oxidative decomplexation of the dioxaborolane ligand from the cyclopropylmethoxide species formed in the dioxaborolane-mediated Simmons–Smith cyclopropanation reaction provided the enantio­enriched CIDA-based (CIDA = N-cyclohexyliminodiacetic acid) boro­cyclopropane in 92% yield and 95.6:4.4 er. A robustness screen has shown diethanolamine to be compatible with esters, carbamates and N-heterocycles, providing a tool to access enantioenriched cyclopropanes carrying not only base-sensitive but oxidizable functional groups as well. Diethanolamine was found to be compatible with the modified zinco-cyclopropanation reaction of allyl alcohol to remove residual dioxaborolane from the corresponding cis-N-heterocycle cyclopropylmethanol, thereby leading to improved yields.

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