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Reactivity of Bridged Pentelidene Complexes with Isonitriles: A New Way to Pentel‐Containing Heterocycles
Author(s) -
Seidl Michael,
Schiffer Michael,
Bodensteiner Michael,
Timoshkin Alexey Y.,
Scheer Manfred
Publication year - 2013
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/chem.201301928
Subject(s) - chemistry , substituent , steric effects , adduct , reactivity (psychology) , bicyclic molecule , lewis acids and bases , stereochemistry , medicinal chemistry , heptane , catalysis , organic chemistry , alternative medicine , pathology , medicine
The reaction of [Cp*E{W(CO) 5 } 2 ] (E=P ( 1 a ), As ( 1 b ); Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) with isonitriles RNC (R= t Bu, cyclohexyl (Cy), n Bu) depends on the steric demand of the substituent at the isonitrile as well as on the stoichiometry of the starting materials. With t BuNC only the Lewis acid/base adducts [Cp*E{W(CO) 5 } 2 (CN t Bu)] (E=P ( 2 a ), As ( 2 b )) are formed. The use of Cy and n ‐butylisonitrile leads first to the formation of the Lewis acid/base adduct, but only at low temperatures. At ambient temperatures, a rearrangement occurs and bicyclo[3.2.0]heptane derivatives of the type [{C(Me)C(CH 2 )C(Me)C(Me)C(Me)}C(NR)‐ E{W(CO) 5 } 2 ] (E=P, As; R=Cy, n Bu) ( 3 a‐Cy , 3 b‐Cy , 3 a‐ n Bu and 3 b‐ n Bu ) are obtained. The use of a further equivalent of isonitrile results in products revealing two new structural motifs, the four‐membered ring derivatives [C(Cp*)N(R)C(NR)E{W(CO) 5 } 2 ] ( 4 : E=P, As; R=Cy, n Bu) and the bicyclic complexes [[{C(Me)C‐ (CH 2 )C(Me)C(Me)C(Me)}C(NR) 2 ‐ E{W(CO) 5 } 2 ] ( 5 : E=As; R=Cy). The reaction pathway depends on the substituent at the isonitrile. By treatment of 1 a with two equivalents of CyNC only a 2 H ‐1,3‐azaphosphet complex 4 a‐Cy (E=P; R=Cy) is formed. Treatment of 1 b with two equivalents of CyNC exclusively leads to the complex 5 b‐Cy (E=As; R=Cy). Treatment of 1 a with two equivalents of n BuNC results in a mixture of complexes, the 2 H ‐1,3‐azaphosphet 4 a‐ n Bu (E=P; R= n Bu) and the bicyclic complex 5 a‐ n Bu (E=P; R= n Bu). For the arsenidene complex 1 b a mixture of the 2 H ‐1,3‐azarsete complex 4 b‐ n Bu (E=As; R= n Bu) and the bicyclic complex 5 b‐ n Bu (E=P, As; R=Cy, n Bu) is obtained. Complex 4 b‐ n Bu is the first example of a 2 H ‐1,3‐azarsete complex. All products have been characterized by using mass spectrometry, NMR spectroscopy, and X‐ray diffraction analysis.