PARTIAL AND TOTAL DEPROTONATION OF THE METHYL-GROUP OF ACETONE UNDER MILD CONDITIONS WITH CONCOMITANT C-C AND N-H BOND FORMATIONS

Acetone adds intramolecularly to a coordinated diazabutadiene in fac-[ Mn(CO)s(tBuN=CHCH=N(t)Bu)(CH3COCH3)]ClO4, 2, to yield fac-[Mn(CO)3{(t) BuN=CHCH(CH2COCH3)N(H)tBu}]ClO4, 8, a [3.2.1] bicyclic complex contain ing a ketone-amino-imino ligand. Compound 3 is deprotonated by KOH to give the enolate derivative fac-[Mn(CO)3{(t)BuN=CHCH(CH=C{O}CH3)N(H)(t )Bu}], 4, which reacts with CNtBu to afford a [2.2.1] bicyclic complex , Mn(CO)3{(t)BuN=CHCH(C{=CN(H)tBu}COCH3)N(H)(t)Bu}], 5. In each of the se three reactions, an acetone methyl group loses a hydrogen and resul ts overall in fully deprotonated 5. On the other hand, the coordinated ketone carbonyl group in the fac-tricarbonyl complex 3 is smoothly re placed by CN(t)Bu to generate another tricarbonyl derivative, CO)3(CN- (t)Bu){tBuN=CHCH(CH2COCH3)N(H)(t)Bu}]ClO4, 6, which reacts with a seco nd isocyanide to give the dicarbonyl compound n(CO)2(CN(t)Bu)2{(t)BuN= CHCH(CH2COCH3)N(H)-(t)Bu}] ClO4, 7. Upon heating, 6 loses a carbonyl C O ligand and rearranges to yield a [3.2.1] bicyclic dicarbonyl complex O)2(CN(t)Bu){(t)BuN=CHCH(CH2COCH3)N(H)(t)Bu}]ClO4, 8. In complexes 6 and 7, the acetone-amino-imino ligand acts in a N,N'-bidentate fashion , while in 8, it acts again as a tridentate ligand. The structure of 5 has been determined by X-ray diffraction methods: M = 446.44, monocli nic, space group P2(1)/n, a = 8.530(2) angstrom, b = 18.47(1) angstrom , c = 15.375(8) angstrom, beta = 103.04(2)-degrees, V = 2361(2) angstr om3, Z = 4, D(x) = 1.25 g cm-3, Mo Kalpha radiation (graphite crystal monochromator, lambda = 0.710 73 angstrom), mu = 5.63 cm-1, F(000) = 9 48, T = 200 K; final conventional R factor 0.028 for 3155 ''observed' reflections and 365 parameters.