ChemInform Abstract: Synthesis of Phosphonium Salts, Phosphorus Ylides and Unsaturated Ketones of 3‐ and 5‐Acetyl Derivatives of Acenaphthene.

Abstract

Aus 3‐ bzw. 5‐Bromacetylacenaphthen (I) entstehen die Phosphoniumsalze (II) und weiter die Phosphorylide (III).

Solvent reduced wittig olefination reactions with halo containing conjugated phosphoranes

“…Acyl-and alkyloxycarbonylhalomethylidenetriphenylphosphoranes 3, 4, 7, 9 and 12 were synthesized by halogenation -dehydrohalogenation [12][13][14][15] of the corresponding phosphoranes 2, 6, 8, and 11, where bromine/triethylamine (Et 3 N) [13] and N -bromosuccinimide (NBS)/K 2 CO 3 [bromination -dehydrobromination] [14] and iodomonobromide/Et 3 N [iodobromination -dehydrobromination] [15] were used as reagent/base systems (Scheme 1). The halogenated phosphoranes were subjected to flash column chromatography.…”

“…The extended phosphorane, 8, was prepared by Suzuki coupling of bromophenacylmethylidenetriphenylphosphorane, 6b, with o-tolylboronic acid [23]. Compounds 3, 9, and 12 were prepared by bromination/dehydrobromination of 2: 3a, 3b, 3c [22, b,c] and 12a (all utilizing Et 3 N/Br 2 [13]), or 9a, 9b and 9c (all utilizing NBS, K 2 CO 3 , THF [14]). Compounds 4, 7 and 12b were prepared by iodobromination and dehydrobromination (all utilizing IBr, Et 3 N [15]).…”