Novel approach to biscarbazole alkaloids via Ullmann coupling--synthesis of murrastifoline-A and bismurrayafoline-A.

  title={Novel approach to biscarbazole alkaloids via Ullmann coupling--synthesis of murrastifoline-A and bismurrayafoline-A.},
  author={Carsten B{\"o}rger and Olga N. Kataeva and Hans‐Joachim Kn{\"o}lker},
  journal={Organic \& biomolecular chemistry},
  volume={10 36},
Unprecedented Ullmann couplings of murrayafoline-A with either 6-bromo- or 4-bromocarbazole derivatives provide highly efficient synthetic routes to the biscarbazole alkaloids murrastifoline-A (6 steps, 66% overall yield) and bismurrayafoline-A (6 steps, 28% overall yield). 
Synthesis of Methylene-Bridged Biscarbazole Alkaloids by using an Ullmann-type Coupling: First Total Synthesis of Murrastifoline-C and Murrafoline-E.
This work describes the total synthesis of methylene-bridged biscarbazole alkaloids by using a late-stage Ullmann-type coupling of fully functionalised carbazole subunits through a sequence of palladium(0)- and palladium (II)-catalysed coupling reactions.
Total synthesis of the biscarbazole alkaloids murrafoline A-D by a domino sonogashira coupling/claisen rearrangement/electrocyclization reaction.
Aryl-pyran-linked biscarbazole alkaloids of the murrafoline group were accessed readily by a novel domino reaction sequence involving Sonogashira coupling, a Claisen rearrangement, and electrocyclization, and the one-pot procedure enables the straightforward synthesis of these structurally challenging alkal steroids in only a few steps.
An unprecedented benzannulation of oxindoles with enalcarbenoids: a regioselective approach to functionalized carbazoles.
A novel Rh(ii)/Brønsted acid catalyzed tandem benzannulation of oxindoles with enaldiazo carbonyls led to the formation of valuable 1-hydroxy-2-acylcarbazoles. This reaction is proposed to involve a
Brønsted acid-catalyzed synthesis of carbazoles from 2-substituted indoles
A simple and efficient method for the synthesis of disubstituted carbazoles has been developed. In this approach, carbazoles are synthesized from o-haloanilines and terminal alkynes using a two-step
First total syntheses of chrestifoline-B and (±)-chrestifoline-C, and improved synthetic routes to bismurrayafoline-A, bismurrayafolinol and chrestifoline-D.
We describe an efficient synthesis of the methylene-bridged biscarbazole alkaloids bismurrayafoline-A, bismurrayafolinol and chrestifoline B-D using an Ullmann-type coupling at the benzylic position.
Efficient synthesis of biscarbazoles by palladium-catalyzed twofold C-N coupling and C-H activation reactions.
A new and efficient strategy for the synthesis of 3,9'- and 2,9'-biscarbazoles was developed. Our strategy relies on the cyclization of 1,1'-biphenyl-2,2'-diyl bis(trifluoromethanesulfonate) with 4-
Procedure for the Synthesis of Polysubstituted Carbazoles from 3-Vinyl Indoles.
A simple Brønsted acid catalyzed tandem reaction, including intermolecular nucleophilic addition, substitution and intramolecular cyclization, in a one-pot manner is described and the poly(1,4-carbazole) is prepared for the first time.
Iodine-catalyzed aromatization of tetrahydrocarbazoles and its utility in the synthesis of glycozoline and murrayafoline A: a combined experimental and computational investigation.
A new protocol for the aromatization of tetrahydrocarbazoles has been achieved using a catalytic amount of iodine, giving high yields, and has proven to be tolerant of a broad range of functional groups.


Total synthesis of murrastifoline-A by way of the Pd-catalyzed double N-arylation of a carbazolamine with a 2,2′-dibromobiphenyl derivative
The first total synthesis of murrastifoline-A (1), a biscarbazole alkaloid is described. The biscarbazole skeleton of 1 was effectively constructed by the Pd-catalyzed double N-arylation of
A new route to 1-oxygenated carbazoles. Synthesis of murrayafoline-a
Abstract 1-Oxygenated carbazoles are prepared in four steps from indole-2-carboxylates by Claisen condensation with butyrolactones, followed by hydrolysis with concomitant decarboxylation, oxidation,
A Concise Synthesis of the Natural Carbazole Mukonine
A short and total synthesis of the natural carbazole mukonine (1) is described, based on a regioselective Diels-Alder reaction of N-phenyl 4,5-dimethylidene-2-oxazolidinone (9) with methyl propiolate
Regioselective synthesis of 1-hydroxycarbazoles via anionic [4+2] cycloaddition of furoindolones : a short synthesis of murrayafoline-A
Suitably N-protected furoindolones react regioselectively with a variety of Michael acceptors in the presence of LDA to give 1-hydroxycarbazoles in a single-pot process and in good yields. The
A new synthesis of the 1-oxygenated 1,3-disubstituted carbazole alkaloids, mukonine (la) and clausine (If) is described. The construction of the carbazole framework is based on an allene-mediated
A new two step route to 1-hydroxy-9H-3-carbazolecarboxylic acid derivatives from 3-formylindole. Application to the synthesis of mukonine
Abstract Carbazole alkaloid mukonine 6b was prepared from 3-formylindole in three steps (32% overall yield). The key step was the base-promoted cyclization of a mixed anhydride of mono ester mono
Efficient iron-mediated approach to pyrano[3,2-a]carbazole alkaloids--first total syntheses of O-methylmurrayamine A and 7-methoxymurrayacine, first asymmetric synthesis and assignment of the absolute configuration of (-)-trans-dihydroxygirinimbine.
Iron-mediated oxidative cyclisation provides an efficient approach to pyrano[3,2-a]carbazole alkaloids. Thus, improved routes to girinimbine and murrayacine as well as the first total syntheses of
Indoloquinones, Part 8. Palladium(II)-catalyzed Total Synthesis of Murrayaquinone A, Koeniginequinone A, and Koeniginequinone B
Regioselective addition of the appropriate arylamines to 2-methyl-1,4-benzoquinone followed by a palladium(II)-catalyzed oxidative cyclization opens up an efficient route to the naturally occurring
One-step construction of carbazoles by way of the palladium-catalyzed double N-arylation reaction and its application to the total synthesis of murrastifoline-A
Abstract The one-step construction of N-substituted carbazoles by way of the Pd-catalyzed double N-arylation reaction of primary amines with 2,2′-dibromobiphenyl is described. Aryl and aliphatic