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An Unprecedented Type of Migratory Insertion Reactions of Unsaturated C 3 Units into Rh−O and Rh−C Bonds
Author(s) -
Werner Helmut,
Wiedemann Ralf,
Laubender Matthias,
Windmüller Bettina,
Wolf Justin
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010504)7:9<1959::aid-chem1959>3.0.co;2-7
Subject(s) - chemistry , medicinal chemistry , bond cleavage , stereochemistry , cleavage (geology) , catalysis , organic chemistry , materials science , fracture (geology) , composite material
A series of iodo‐ and hydroxorhodium( I ) complexes of the general composition trans ‐[RhX(=C=C=CRR′)(P i Pr 3 ) 2 ] (X=I: 5 – 7 ; X=OH: 8 – 11 ) was prepared from the related chlororhodium( I ) precursors. The hydroxo compounds behave as organometallic Brønsted bases and react with acids like MeCO 2 H, PhCO 2 H, PhOH, or TsOH by elimination of water to give the substitution products trans ‐[RhX′(=C=C=CRR′)(P i Pr 3 ) 2 ] (X′=MeCO 2 : 12, 13 ; X′=PhCO 2 : 14 ; X′=PhO: 15, 16 ; X′=TsO: 17, 18 ) in good to excellent yields. In contrast to the tosylates 17, 18 , which react with CO by cleavage of the allenylidene–metal bond to give trans ‐[Rh(OTs)(CO)(P i Pr 3 ) 2 ] ( 19 ), treatment of the acetato and phenolato derivatives 12, 13 and 15, 16 with CO affords by migratory insertion of the allenylidene unit into the Rh−O bond the alkynyl complexes trans ‐[Rh{C≡CCR(R′)X′}(CO)(P i Pr 3 ) 2 ] (X′=MeCO 2 : 20, 21 ; X′=OPh: 22, 23 ). Similarly, the reactions of the hydroxo compounds 8, 10 , and 11 with CH 2 (CN) 2 and either CO or CNMe yield the carbonyl and the isocyanide complexes trans ‐[Rh{C≡CCR(R′)CH(CN) 2 }(L′)(P i Pr 3 ) 2 ] (L′=CO: 25 – 27 ; L′=CNMe: 28 – 30 ), respectively. By protolytic cleavage of the Rh−C σ bond the γ ‐functionalized alkynes HC≡CCR(R′)CH(CN) 2 ( 31, 32 ) are generated from 25, 26 and HCl in benzene. The molecular structure of 22 was determined by X‐ray crystallography.