13 Boron “Ate” Complexes for Asymmetric Synthesis
Book
Editor: Fernández, E.
Title: Advances in Organoboron Chemistry towards Organic Synthesis
Print ISBN: 9783132429710; Online ISBN: 9783132429758; Book DOI: 10.1055/b-006-164898
1st edition © 2020. Thieme. All rights reserved.
Georg Thieme Verlag KG, Stuttgart
Subjects: Organic Chemistry;Chemical Reactions, Catalysis;Organometallic Chemistry;Laboratory Techniques, Stoichiometry
Science of Synthesis Reference Libraries
Parent publication
Title: Science of Synthesis
DOI: 10.1055/b-00000101
Series Editors: Fürstner, A. (Editor-in-Chief); Carreira, E. M.; Faul, M.; Kobayashi, S.; Koch, G.; Molander, G. A.; Nevado, C.; Trost, B. M.; You, S.-L.
Type: Multivolume Edition
Abstract


Addition of a nucleophile to a boronic ester results in the generation of a tetravalent boronate “ate” complex. If there is a leaving group stationed on the carbon atom α to the boron atom, the boronate complex can undergo stereospecific 1,2-migration with simultaneous expulsion of the leaving group to form a homologated boronic ester. The enantioselectivity of the process is dictated by either incorporating a chiral substituent into the boronic ester component (substrate control), or by forming a boronate complex through the addition of an enantioenriched carbenoid species to a boronic ester (reagent control). Activation of a boronic ester with organolithium reagents generates a nucleophilic boronate complex that acts as a chiral organometallic-type reagent, reacting with a wide range of electrophiles with inversion of stereochemistry. This chapter discusses methodology available for the enantioselective homologation of boronic esters using both substrate- and reagent-controlled strategies, and the development of boronate complexes as chiral nucleophiles.