A Novel Entry to 17α-Bromo- and 17α-Iodoethynyl Steroids

  title={A Novel Entry to 17$\alpha$-Bromo- and 17$\alpha$-Iodoethynyl Steroids},
  author={Helmut Hofmeister and Klaus Dr Annen and Henry Laurent and Rudolf Prof. Dr. Wiechert},
  journal={Angewandte Chemie},
Halogen bond-induced electrophilic aromatic halogenations.
This review highlights the evolution of the two modes of activation in N-Halosuccinimides and 1,3-dihalo-5,5-dimethylhydantoins and evidence of halogen bond formation from mechanistic studies of nucleophilic activation is discussed herein.
Diethyl (iodoethynyl)phosphonate and (iodoethynyl)diphenylphosphane oxide: crystal structures and some cycloaddition reactions
Abstract The title compounds are difunctionalized acetylenic building blocks, which can serve as electrophilic dienophiles and dipolarophiles in [4+2] and azide-iodoalkyne [3+2] cycloaddition
Nucleophile-assisted cyclization of β-propargylamino acrylic compounds catalyzed by gold(i): a rapid construction of multisubstituted tetrahydropyridines and their fused derivatives
Au(I)-catalyzed cyclization of β-propargylamino acrylic derivatives 1, carried out in the presence of methanol, afforded tetrahydropyridines 3 in high isolated yields. An intramolecular version,
Catalytic Enantioselective Carbonyl Propargylation Beyond Preformed Carbanions: Reductive Coupling and Hydrogen Auto‐Transfer
Chiral metal complexes catalyze enantioselective carbonyl propargylation via reductive coupling or as hydrogen auto‐transfer processes, in which reactant alcohols serve dually as reductant and
Copper(I)-Catalyzed Stereodivergent Propargylation of N-Acetyl Mannosamine for Protecting-Group-Minimal Synthesis of C3-Substituted Sialic Acids.
Copper(I)-catalyzed stereodivergent nucleophilic propargylation at the anomeric carbon of unprotected N-acetyl mannosamine was developed using 3-substituted allenylboronates as a nucleophile and was concisely transformed into C3-substantiated sialic acids in two steps without the use of protecting groups.
Synthesis of Unsymmetrical Derivatives of Pentacene for Materials Applications.
The study of intramolecular singlet fission (iSF) has emerged as one of the most fruitful applications of unsymmetrical pentacene derivatives, andDimeric pentacenes are central to providing an in-depth understanding of the molecular mechanism of SF, often providing advances not possible from measurements in the solid state.


No‐carrier‐added bromination of estrogens with chloramine‐t and Na77Br
The syntheses of monobromohexestrol and 17α-bromoethynylestradiol are described as examples of bromination of phenolic and ethynyl moieties using Chloramine-T. This technique represents a unique
Solvent Incorporation in Bromination of Acetylenes in Alcohols
The reactions of acetylenes with bromine in alcohols at 20–25 °C afford dibromodialkoxyalkanes in good yields together with variable amounts of dibromoalkenes. Similar treatment of phenylacetylene
11‐Alkylidene steroids in the 19‐nor series
A number of 11-methylene-substituted estrenes and 19-nor-pregnenes have been synthesised. In addition, some 11-(E)-ethylidene estrenes have been prepared. Evidence is presented establishing the
Synthesis of D-norgestrel.
The regioselective sulfonylmethylation of optically active 7a beta-ethyl-6H-77a-dihydroindan-15-dione opens the possibility of a new technically simpler synthesis of d-norgestrel by ethynylation.