ORGANIC SYNTHESES VIA TRANSITION-METAL COMPLEXES .69. 2-(ACYLAMINO)ETHENYL KETENE IMINES FROM [2-(ACYLAMINO)ETHENYL]CARBENE COMPLEXES AND THEIR RING-CLOSING METATHESIS TO PYRROLES OR ELECTROCYCLIZATION TO 1,4-DIAMINONAPHTHALENES

[2-(Acylamino)ethenyl]carbene complexes L(n)M=C(OEt) -CH=CPh-[N(COR)Ph] 5 [L(n)M=(CO)5Cr, (CO)5W(i) R=C6H5, pMeOC6H4, pNO2C6H4, OtBu] are obtained by N-acylation of [2-(amino)ethenyl]carbene complexes L(n)M=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-degrees-C gives the isocyanide complexes L(n)M(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=degrees-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-degrees-C leads to the formation of 1,4-diaminonaphthalenes, e.g. 12g (>95% yield), by an electrocyclic ring closure.