REARRANGEMENT IN THE REACTION OF CHLOROBENZENE-1-C¹⁴ WITH POTASSIUM AMIDE¹

Abstract

While 2,3,5-tri-O-benzoyl-D-ribose shows little if any mutarotation in chloroform or aqueous dioxane, methylation studies and comparisons between its rotation and those of some closely related substances (both to be published in the near future) appear to justify the tentative conclusion that it belongs to the /3-D-series.Acetylation of 2,3,5-tri-O-benzoyl-D-ribose in pyridine at a low temperature afforded in 88% yield crystalline l-O-acetyl-2,3,5-tri-O-benzoyl-D-ribose [m.p. 130-131°( cor.); [ ]'20 +44.2°(CHCU)].Similarly, benzoylation at low temperature gave in 89% yield D-ribofuranose tetrabenzoate [m.p. 121-122°( cor.); [a]20D +17.0 (CHC1*)]; the same substance was also obtained through the benzoylation of D-ribose in pyridine at 100°although the yield in this case (11%) was low owing to the difficulty of separating the product from /3-D-ribopyranose tetrabenzoate which is formed simultaneously.2,3,5-Tri-O-benzoyl-D-ribose has been used for the synthesis of benzyl d-D-ribofuranpside tribenzoate;it is possible that it may prove of general utility for the synthesis of ribofuranosides.

Synthesis, Structure, and Bonding of a Zirconocene–1,2‐Dehydro‐o‐carborane Complex

“…In the anion, the Zr center is h 5 -bound to the five-membered ring of the indenyl group, h 3 -bound to a 1,2-dehydro-o-carborane moiety, and s-bound to a cage carbon atom and a terminal chlorine atom in a distorted-tetrahedral geometry. The average Zr À C-(C 5 ring) bond lengths of 2.515(5) , Zr À Cl bond length of 2.403(2) , and Zr-C2 bond length of 2.359(5) are close to the corresponding values found in [{h 5 :s-Me 2 C-(C 9 H 6 )(C 2 B 10 H 10 )}ZrCl(m-Cl) 1.5 ] 2 À .…”

“…After removal of the precipitate, the clear brown solution was concentrated to about 10 mL and cooled to À30 8C to give 1 as light-brown crystals (260 mg, 60 %). 1 …”

The Discovery and Development of Metal-Free Arylation Reactions with Unsymmetrical Diaryliodonium Salts

“…82 The ratio of isomers formed by 4-substituted and 3-subsitituted benzynes are in line with the ratios formed by this reaction of unsymmetrical diaryliodonium salts (Scheme 3.11). 83 …”

“…In this experiment, the aryne was successfully trapped by furan to form the cycloadduct 6-(trifluoromethyl)-1,4-dihydro-1,4-epoxynaphthalene 2c in high yield (Scheme 3.12). The reaction was highly selective in forming only one aryne product in 82 addition to the by-product mesityl iodide 2d in 1:1 ratio. To the best of our knowledge, this is the highest yield reported for the C-H deprotonation product of diaryliodonium salts since the first seminal reports in 1974-75 discussed in the above literature precedent section (Scheme 3.6).…”

“…53 The authors proposed an elimination-addition mechanism involving an electronically neutral species they labeled "benzyne" based on several observations made, such as; a) the amination reactions are very fast, b) the amine group is always attached only one carbon away from the leaving halide, no reaction was observed when there was no C-H group ortho to the halide (e.g.…”