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Intramolecular Ring Expansion of a 2‐Lithium‐anilido‐2‐fluoro‐1,3‐diaza‐2‐silacyclopentene to a 1,3,5‐Triaza‐7‐bora‐2‐silacycloheptene – Experimental and Quantum‐chemical Results
Author(s) -
Abraham Sascha,
Schmatz Stefan,
Klingebiel Uwe,
Fischer Andreas
Publication year - 2010
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.200900341
Subject(s) - intramolecular force , chemistry , lithium (medication) , bicyclic molecule , fluoride , ring (chemistry) , medicinal chemistry , stereochemistry , crystallography , inorganic chemistry , organic chemistry , medicine , endocrinology
The reaction between the lithiated 2‐diisopropylanilino‐2‐fluoro‐1,3‐diaza‐2‐silacyclopentene, (HCNCMe 3 ) 2 SiFNLi(2,6‐Me 2 CH) 2 C 6 H 3 ( I ), and BF 3 ·OEt 2 in THF afforded in an unknown, intramolecular ring expansion the seven‐membered 1,3,4‐triaza‐7‐bora‐2‐silacycloheptene, (HCNCMe 3 ) 2 (SiF 2 )BFN‐2,6‐(Me 2 CH) 2 C 6 H 3 ( 1 ). Starting with the BF 2 ‐substituted compound A , quantum‐chemical calculations on the thermal isomeration process revealed a two‐step reaction mechanism: First, the bicyclic compound C is formed via transition state TS1 , and second, a 1,3‐fluoride ion migration occurs in the seven‐membered transition state TS2 from a BF 2 ‐ to a SiF‐unit. The reaction mechanism and the structures of the transition states are discussed in detail.