24314-51-0Relevant articles and documents
Highly functionalized donor-acceptor cyclopropanes applied toward the synthesis of the Melodinus alkaloids
Goldberg, Alexander F.G.,Craig, Robert A.,O'Connor, Nicholas R.,Stoltz, Brian M.
, p. 2983 - 2990 (2015/05/27)
Abstract A series of highly substituted vinylcyclopropanes were prepared and examined as reaction partners in a palladium-catalyzed (3+2) cycloaddition with nitrostyrenes. Described herein are our efforts to synthesize an elusive 1,1-divinylcyclopropane by several distinct approaches, and to apply surrogates of this fragment toward the synthesis of the Melodinus alkaloids.
Synthesis studies on the Melodinus alkaloid meloscine
Feldman, Ken S.,Antoline, Joshua F.
, p. 1434 - 1445 (2013/02/25)
The pentacyclic Melodinus alkaloid (±)-meloscine was synthesized in 19 chemical steps from 2-bromobenzaldehyde through a route featuring an allenyl azide cyclization cascade to deliver the core azabicyclo[3.3.0]octane substructure. Peripheral functionalization of this core included a Tollens-type aldol condensation to set the quaternary center at C(20) and a diastereoselective ring-closing metathesis to forge the tetrahydropyridine ring.
Allenyl azide cycloaddition chemistry: Application to the total synthesis of (±)-meloscine
Feldman, Ken S.,Antoline, Joshua F.
, p. 934 - 937 (2012/05/05)
The pentacyclic alkaloid (±)-meloscine was prepared in 19 steps through a reaction sequence that features a putative azatrimethylenemethane intermediate, generated through cascade cyclization of an allenyl azide substrate, to deliver the core azabicyclo[3
A short total synthesis of (±)-epimeloscine and (±)-meloscine enabled by a cascade radical annulation of a divinylcyclopropane
Zhang, Hanmo,Curran, Dennis P.
, p. 10376 - 10378 (2011/08/05)
The first stereoselective synthesis of epimeloscine has been accomplished in 13 total steps with a longest linear sequence of 10 steps. The core of the synthesis takes only five steps, the key ones being acylation, stereoselective tandem radical cyclization of a divinylcyclopropane to make two rings, and group-selective ring-closing metathesis of the resulting divinylcyclopentane to make the last ring.
Total synthesis of (±)-meloscine
Hayashi, Yujiro,Inagaki, Fuyuhiko,Mukai, Chisato
supporting information; experimental part, p. 1778 - 1780 (2011/05/30)
The total synthesis of (±)-meloscine was completed in a highly stereoselective manner starting from the known 4-(2-aminophenyl)-2,3-dihydro-N- methoxycarbonylpyrrole. The crucial step in this total synthesis involves the efficient construction of the tetr
Total synthesis of meloscine by a [2+2]-photocycloaddition/ring-expansion route
Selig, Philipp,Herdtweck, Eberhardt,Bach, Thorsten
experimental part, p. 3509 - 3525 (2010/01/11)
The unusual monoterpenoid indole alkaloid meloscine was synthesized starting from a protected aminoethylquinolone in 15 steps and an overall yield of 9%, employing a [2+2]-photocycloaddition as the stereochemistry defining key step. After the initial plan of a Wagner-Meerwein type rearrangement of a [4.2.0]- into a [3.3.0]-bicyclic substructure could not be realized, the required ring enlargement of a cyclobutane was eventually achieved by a retro-benzilic acid rearrangement. Generation of the central pyrrolidine ring was possible by a three-step reductive amination domino sequence. The final ring was built up by a ring-closing metathesis after the last quaternary stereocenter had been constructed by a Johnson-Claisen rearrangement. The synthesis was concluded by a selenylation-elimination sequence to build up the exocyclic vinyl group of meloscine. Using our methodology for enantioselective [2+2]-photocycloaddition mediated by a chiral complexation agent, the experimentally very simple synthesis could be performed in an enantioselective fashion (7% overall yield). The enantioselective synthesis of (+)-meloscine represents the first example of a natural product synthesis employing an enantioselective [2+2]-photocycloaddition as its key step, and illustrates nicely the synthetic potential of photochemical transformations for the construction of complex heterocyclic structures.
Enantioselective total synthesis of the Melodinus alkaloid (+)-meloscine
Selig, Philipp,Bach, Thorsten
scheme or table, p. 5082 - 5084 (2009/03/11)
(Chemical Equation Presented) Enantioselective synthesis in a new light: The template-controlled [2+2] photocycloaddition leading to product 1 is the first example of this type of reaction in natural product synthesis. In addition, a retrobenzilic acid rearrangement (→2), a Claisen rearrangement (→3), and a ring-closing metathesis played decisive roles in the synthesis of the alkaloid (+)-meloscine (4).
Uses of aza-cope rearrangement-mannich cyclization reactions to achieve a general entry to melodinus and aspidosperma alkaloids. stereocontrolled total syntheses of (±)-deoxoapodine, (±)-meloscine, and (±)-epimeloscine and a formal synthesis of (±)-1-acetylaspidoalbidine
Overmann, Larry E.,Robertson, Graeme M.,Robichaud, Albert J.
, p. 2598 - 2610 (2007/10/02)
The first total syntheses of the structurally unusual pentacyclic Melodinus alkaloids (±)-meloscine (1) and (±)-epimeloscine (2) and the hexacyclic Aspidosperma alkaloids (±)-deoxoapodine (4) are reported. The syntheses proceed via a highly functionalized common tetracyclic intermediate 7, which is accessed (with complete stereocontrol) by the title rearrangement of pyrindinol 10. These syntheses provide excellent examples of the power of tandem of aza-Cope rearrangement-Mannich cyclization reactions as the key element of stereocontrolled alkaloid synthesis design.
Total Synthesis of (+/-)-Meloscine and (+/-)-Epimeloscine
Overman, Larry E.,Robertson, Graeme M.,Robichaud, Albert J.
, p. 1236 - 1238 (2007/10/02)
Total syntheses of the Melodinus alkaloids (+/-)-meloscine and (+/-)-epimeloscine are reported.These are the first reported total syntheses of members of this structurally unique alkaloid class.
