17322-84-8Relevant academic research and scientific papers
Application of Electrocyclic Ring-Opening and Desymmetrizing Nucleophilic Trappings of meso-6,6-Dibromobicyclo[3.1.0]hexanes to Total Syntheses of Crinine and Haemanthamine Alkaloids
Lan, Ping,Banwell, Martin G.,Willis, Anthony C.
, (2019/03/19)
The thermally induced electrocyclic ring-opening of C2-symmetric (meso) 6,6-dibromobicyclo[3.1.0]hexanes such as 10 in the presence of the chiral, nonracemic 1°-amine 28 afforded a ca. 1:1 mixture of the diastereoisomeric and chromatographically separable 1-amino-2-bromo-2-cyclohexenes 37 (42%) and 38 (45%). Each of these was elaborated over 13 steps, including Suzuki-Miyaura cross-coupling, radical cyclization, and Pictet-Spengler reactions, into (-)- or (+)-crinane (1 or ent-1, respectively). Variations on these protocols were applied to the total syntheses of (+)- and (-)-11-hydroxyvattitine [(+)- and (-)-3], (+)- and (-)-bulbispermine [(+)- and (-)-4], (+)- and (-)-haemanthamine [(+)- and (-)-5], (+)- and (-)-pretazettine [(+)- and (-)-6], and (+)- and (-)-tazettine [(+)- and (-)-7] as well as (±)-hamayne [(±)-8] and (±)-apohaemanthamine [(±)-9]. A number of these alkaloids were synthesized for the first time.
Total syntheses of (-)-haemanthidine, (+)-pretazettine, and (+)-tazettine
Baldwin, Steven W.,Debenham, John S.
, p. 99 - 102 (2007/10/03)
(matrix presented) Haemanthidine Pretazettine Tazettine The total syntheses of the amaryllidaceae alkaloids haemanthidine, pretazettine, and tazettine as optically pure enantiomers are reported. Using D-mannose as the starting material, the critical relat
Construction of quaternary carbon centers by palladium-catalyzed intramolecular alkene insertions. Total synthesis of the amaryllidaceae alkaloids (±)-tazettine and (±)-6a-epipretazettine
Abelman, Matthew M.,Overman, Larry E.,Tran, Vinh D.
, p. 6959 - 6964 (2007/10/02)
Total syntheses of (±)-tazettine (1) and (±)-6a-epipretazettine (3), which proceed in 11 steps from the known enal 7(14 steps from commercially available p-methoxybenzyl alcohol), are reported. The pivotal step is the palladium-catalyzed cyclization of alkenyl aryl iodide 13, which proceeded in excellent yield (63-90%) and with high stereoinduction (>20:1) to form 14.
Phenolic Oxidative Coupling with Hypervalent Iodine. A Synthesis of 6a-Epipretazettine
White, James D.,Chong, Wesley K. M.,Thirring, Klaus
, p. 2300 - 2302 (2007/10/02)
6a-Epipretazettine was synthesized in seven steps from piperonal and synephrine.Intramolecular, monophenolic, oxidative coupling of a functionalized benzylic acetal, employing benzene as oxidant, gave a spirodienone in 13 percent yield.Subsequent deprotection of the secondary amine was followed by spontaneous closure to a tetracyclic pyrrolidine possessing an all-cis ring fusion.This substance was reduced with diisobutylaluminum hydride, and the resulting alcohol was transformed, via methanolysis of the corresponding mesylate, to O-methyl-6a-epipretazettine.Acidic hydrolysis of the latter yielded 6a-epipretazettine, identical with material previously obtained by Danishefsky.
Total Synthesis of dl-Tazettine and 6a-Epipretazettine: A Formal Synthesis of dl-Pretazettine. Some Observations on the Relationship of 6a-Epipretazettine and Tazettine
Danishefsky, Samuel,Morris, Joel,Mullen, George,Gammill, Ronald
, p. 7591 - 7599 (2007/10/02)
Diels-Alder cycloaddition of dienophile 26 with diene 8 produces the protected 4-aryl-4-acylcyclohexadienone 37.This is converted in two steps to the oxidized mesembrine derivative 11.Through the novel use of trimethyl orthoformate as a C1 inte
