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Metal Halide Exchange in Benzylborane NHC‐Adducts: The Effect of Backbone Alkylation in the N ‐Heterocyclic Carbene
Author(s) -
Wullschläger Daniela,
Denker Lars,
Frank René
Publication year - 2022
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202200018
Subject(s) - chemistry , silylation , moiety , carbene , alkylation , medicinal chemistry , trimethylsilyl , adduct , boranes , halide , bromide , lithium amide , lithium (medication) , polymer chemistry , stereochemistry , organic chemistry , boron , catalysis , enantioselective synthesis , medicine , endocrinology
Among other main group elements, the chemistry of boron has been stimulated by N ‐heterocyclic carbenes (NHCs) as important ligands, the nature of which can significantly control the outcome of reactions. In four‐coordinate benzyl boranes of type (NHC)BH 2 CH 2 ( o ‐BrC 6 H 4 ), we demonstrate this effect at the example of a lithiation silylation procedure. For NHC=I i Pr lithiation of the arene ring by lithium‐bromide exchange with t BuLi ultimately leads to backbone substitution with proton rearrangement, as demonstrated by trapping with trimethylsilyl chloride. In contrast, such process is suppressed for NHC=I i Pr Me , which undergoes lithiation and subsequent trimethyl‐silylation at the arene moiety.