Organische Synthesen mit Übergangsmetallkomplexen, 70. [2‐(Galactopyranosylamino)ethenyl]carben‐ und 3‐(Galactopyranosylamino)‐1,2‐propadienyliden‐Komplexe durch 3‐Addition von 2,3,4,6‐Tetra‐O‐pivaloyl‐β‐D‐galactopyranosylamin an Alkinylcarben‐Komplexe (M = Cr, W). — Atropisomere Galactopyranosyl‐Pyrrole durch Reaktion von [2‐(Galactopyranosylamino)ethenyl]carben‐Komplexen mit Isocyaniden

Abstract

Organic Syntheses via Transition Metal Complexes, 70[1]. — [2‐(Galactopyranosylamino)ethenyl]carbene and 3‐(Galactopyranosylamino)‐1,2‐propadienylidene Complexes on 3‐Addition of 2,3,4,6‐Tetra‐O‐pivaloyl‐β‐D‐galactopyranosylamine to Alkynylcarbene Complexes (M = Cr, W). — Atropisomeric Galactopyranosyl Pyrroles by Reaction of [2‐(Galactopyranosyl‐amino)ethenyl]carbene Complexes with IsocyanidesEnantiomeric pure (2‐aminoethenyl)carbene complexes LnMC(OEt)CHC(Ph)NHR* (Z)‐3 and 3‐amino‐1,2‐propadienylidene complexes LnMCCC(Ph)NHR* 4 [R* = 2,3,4,6‐tetra‐O‐pivaloyl‐β‐D‐galactopyranosyl] are obtained by the addition of galactopyranosylamine R*‐NH2 2 to the corresponding alkynylcarbene complexes LnMC(OEt)CCPh 1 [LnM = (CO)5Cr, (CO)5W]. Treatment of (Z)‐3 with two equivalents of tert‐butyl isocyanide (5) affords isocyanide complexes 6 and ketene imines 7. The latter cyclize spontaneously to give galactopyranosylpyrroles 8 which form stable atropisomers 8A and 8B.