0000000000243019
AUTHOR
László Nyulászi
Ambident PCN Heterocycles: N- and P-Phosphanylation of Lithium 1,3-Benzazaphospholides
Synthetic and structural aspects of the phosphanylation of 1,3-benzazaphospholides 1(Li), ambident benzofused azaphosphacyclopentadienides, are presented. The unusual properties of phospholyl-1,3,2-diazaphospholes inspired us to study the coupling of 1(Li) with chlorodiazaphospholene 2, which led to the N-substituted product 3. Reaction of 1(Li) with chlorodiphenyl- and chlorodicyclohexylphosphane likewise gave N-phosphanylbenzazaphospholes 4 and 5, whereas with the more bulky di-tert-butyl- and di-1-adamantylchlorophosphanes, the diphosphanes 6 and 7 are obtained; in the case of 7 they are isolated as a dimeric LiCl(THF) adduct. Structural information was provided by single-crystal X-ray d…
Ambident Reactivity of P˭CH‒N‒Heterocycles: Lithiation and Substitution Sites
Abstract Benzofused 1H-1,3-azaphospholes are lithiated at the N-atom by tBuLi but phosphinylation takes place at either the N- or the P-atom. Smaller chlorophosphines react at nitrogen, bulkier react at phosphorus. Substituents at C2 promote the latter mode. N-Substituted 2H-1,3-benzazaphospholes undergo CH-metalation or addition at the P˭C bond, depending on the conditions, and allow access to 2-functionally substituted benzazaphospholes or their 2,3-dihydro derivatives, new σ2P,X or σ3P,X hybrid ligands (X=O,P).