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Intramolecular Donor‐Assisted Cyclization of Organotin Compounds
Author(s) -
Mehring Michael,
Löw Christian,
Schürmann Markus,
Jurkschat Klaus
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199905)1999:5<887::aid-ejic887>3.0.co;2-2
Subject(s) - chemistry , intramolecular force , cationic polymerization , ligand (biochemistry) , reactivity (psychology) , tin , medicinal chemistry , bond cleavage , stereochemistry , halide , cleavage (geology) , catalysis , organic chemistry , receptor , medicine , biochemistry , alternative medicine , geotechnical engineering , pathology , fracture (geology) , engineering
New intramolecularly coordinated organotin compounds containing the monoanionic O,C,O‐coordinating ligand {4‐ tert ‐Bu‐2,6‐[P(O)(OEt) 2 ] 2 C 6 H 2 } − have been synthesized by substitution reactions starting from organotin halides. In view of the enhanced reactivity of the intramolecularly coordinated compounds {4‐ tert ‐Bu‐2,6‐[P(O)(OEt) 2 ] 2 C 6 H 2 }SnR 2 R′ ( 2 , R = Ph, R′ = CH 2 SiMe 3 ; 3 , R = R′ = Ph; 6 , R = R′ = Cl), cationic tin species are suggested to occur as intermediates in the formation of the heterocyclic compounds [1(Sn),3(P)‐Ph 2 SnOP(O)(OEt)‐5‐ tert ‐Bu‐7‐P(O)(OEt) 2 ]C 6 H 2 ( 8 ), [1(Sn), 3(P)‐Ph(Me 3 SiCH 2 )SnOP(O)(OEt)‐5‐ tert ‐Bu‐7‐P(O)(OEt) 2 ]C 6 H 2 ( 15 ), and {[1(Sn),3(P)‐Cl 2 SnOP(O)(OEt)‐5‐ tert ‐Bu‐7‐P(O)(OEt)]C 6 H 2 } 2 ( 16 ). The latter compounds are formed by intramolecular cyclizations of pentacoordinate cationic tin species under elimination of ethyl halide. Furthermore, the synthesis of [1(Sn),3(P)‐Ph 2 SnOP(O)(OH)‐5‐ tert ‐Bu‐7‐P(O)(OH) 2 ]C 6 H 2 ( 13 ) is described. Reaction of 8 with an excess of Me 3 SiBr leads to the unexpected formation of {2‐[P(O)(OEt)(OSiMe 3 )]‐4‐ tert ‐Bu‐6‐[P(O)(OEt) 2 ]C 6 H 2 }SnPhBr 2 ( 9 ) as a result of an O–Sn bond cleavage initiated by Me 3 SiBr and subsequent reaction of the intermediate with further Me 3 SiBr under Sn–C bond cleavage. The high donor capacity and the rigidity of the new ligand {4‐ tert ‐Bu‐2,6‐[P(O)(OEt) 2 ] 2 C 6 H 2 } − are demonstrated by X‐ray diffraction analyses of the tetraorganotin compound 2 and the monoorganotin trichloride 6 . Furthermore, the molecular structures of the 2,3,1‐oxaphosphastannoles 8 and 16 are discussed.