ISSN:
0009-2940
Keywords:
[2-(Acylamino)ethenyl]carbene complexes
;
Aminocarbene complexes of chromium and tungsten
;
Ketene imines, 2-(acylamino)ethenyl
;
Pyrroles, synthesis by ring-closing metathesis
;
1,4-Diaminonaphthalenes, synthesis by electrocyclization
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Organic Syntheses via Transition Metal Complexes, 69[1]. - 2-(Acylamino)ethenyl Ketene Imines from [2-(Acylamino)ethenyl]carbene Complexes and their Ring-Closing Metathesis to Pyrroles or Electrocyclization to 1,4-DiaminonaphthalenesHerrn Prof. Helmut Werner zum 60. Geburtstag gewidmet.[2-(Acylamino)ethenyl]carbene complexes LnM = C(OEt) —CH=CPh—[N(COR)Ph] 5 [LnM = (CO)5Cr, (CO)5W; R = C6H5, pMeOC6H4, pNO2C6H4, OtBu] are obtained by N-acylation of [2-(amino)ethenyl]carbene complexes LnM=C (OEt)-CH=CPh(NHPh) (Z)-3 in 72-90% chemical yields with high stereoselectivity. The reaction of (Z) - or (E)-5 with two equivalents of isocyanides RNC 6 (R = cC6H11, tBu) at 20°C gives the isocyanide complexes LnM(RNC) 9 and the [2-(acylamino)ethenyl]ketene imines RN=C=C(OEt)—CH = CPh[N(COR)Ph] 8 (〉95% yields) with configurational retention at the C=C(N) bond. Thermolysis of (Z)-8 (20-80°C) provides an efficient route to pyrroles 11 (90-95%) by a ring-closing metathesis with elimination of isocyanates 10, while the thermolysis of (E)-8, e.g. (E)-8g, at 20°C leads to the formation of 1,4-diaminonaphthalenes, e.g. 12g (〉95% yield), by an electrocyclic ring closure.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941270422
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