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[{LiCH(CH 2 CH 2 OMen)SO 2 Ph} 4 ] (OMen = Menthyl): Synthesis and First Structure of a Chiral Solvent Free Lithiated Sulfone with a Direct Li–C Bond
Author(s) -
Linnert Matthias,
Wagner Christoph,
Merzweiler Kurt,
Steinborn Dirk
Publication year - 2008
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.200700297
Subject(s) - chemistry , intramolecular force , deprotonation , crystal structure , crystallography , molecule , substituent , diastereomer , solvent , stereochemistry , medicinal chemistry , organic chemistry , ion
R*OCH 2 CH 2 CH 2 SO 2 Ph (R*OH = MenOH, (–)‐menthol, ( 3a ); BorOH, (1 S )‐(–)‐borneol, ( 3b )) were found to react with n ‐BuLi in n ‐pentane/ n ‐hexane and toluene/ n ‐hexane under deprotonation yielding LiCH(CH 2 CH 2 OR*)SO 2 Ph (R* = Men, ( 4a ); Bor, ( 4b )) which reacted with n ‐Bu 3 SnCl forming the requisite tri( n ‐butyl)tin compounds n ‐Bu 3 SnCH(CH 2 CH 2 OR*)SO 2 Ph (R* = Men, ( 5a ); Bor, ( 5b )) as diastereomeric mixtures. The identities of 5a and 5b were unambiguously proved by 1 H, 13 C and 119 Sn NMR spectroscopic measurements. Solutions of 4a afforded crystals of [{LiCH(CH 2 CH 2 OMen)SO 2 Ph} 4 ] ( 4a′ ) for which the structure was determined by single‐crystal X‐ray crystallography. Complex 4a′ crystallized in a tetrameric structure without any additional solvent molecules. There were found direct Li–C bonds (Li1–C1/Li2–C20 2.231(9)/2.236(9) Å). The tetrahedral donor set of Li is completed by three oxygen atoms. One oxygen atom comes from the OMen substituent via intramolecular coordination and two oxygen atoms come from SO 2 groups of neighboured LiCH(CH 2 CH 2 OMen)SO 2 Ph moieties. Thus, a heterocubane structure with a Li 4 S 4 core is built up.