Methylene-azaphosphirane as a reactive intermediate.
Reaction of the transient phosphinidene complexes R-P=W(CO)5 with N-substituted-diphenylketenimines leads unexpectedly to the novel 2-aminophosphindoles, as confirmed by an X-ray crystal structure determined for one of the derivatives. Experimental evidence for a methylene-azaphosphirane intermediate was found by using the iron-complexed phosphinidene iPr2N-P=Fe(CO)4, which affords the 2-aminophosphindole together with the novel methylene-2,3-dihydro-1H-benzo[1,3]azaphosphole. Analysis of the reaction pathways with DFT indicates that the initially formed methylene-azaphosphirane yields both phosphorus heterocycles by way of a [1,5]- or [1,3]-sigmatropic shift, respectively, followed by a H-shift. Strain underlies both rearrangements, which causes these remarkably selective conversions that can be tuned by changing the substituents.
Slootweg
J Chris
JC
Department of Organic and Inorganic Chemistry, Faculty of Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
Vlaar
Mark J M
MJ
Vugts
Danielle J
DJ
Eichelsheim
Tanja
T
Merhai
Winita
W
de Kanter
Frans J J
FJ
Schakel
Marius
M
Ehlers
Andreas W
AW
Lutz
Martin
M
Spek
Anthony L
AL
Lammertsma
Koop
K