86636-00-2Relevant academic research and scientific papers
Concise Synthesis of Lamellarin Alkaloids by C-H/N-H Activation: Evaluation of Metal Catalysts in Oxidative Alkyne Annulation
Mei, Ruhuai,Zhang, Shou-Kun,Ackermann, Lutz
supporting information, p. 1715 - 1718 (2017/11/27)
The performance of various transition-metal catalysts was explored in the step-economical synthesis of naturally occurring lamellarin alkaloids by C-H/N-H activation. The oxidative alkyne annulation proceeded efficiently by using sustainable ruthenium(II) catalysis, which set the stage for a concise synthesis of lamellarin D, lamellarin H and derivatives thereof.
β-selective C-H arylation of pyrroles leading to concise syntheses of lamellarins C and I
Ueda, Kirika,Amaike, Kazuma,Maceiczyk, Richard M.,Itami, Kenichiro,Yamaguchi, Junichiro
, p. 13226 - 13232 (2015/03/30)
The first general β-selective C-H arylation of pyrroles has been developed by using a rhodium catalyst. This C-H arylation reaction, which is retrosynthetically straightforward but results in unusual regioselectivity, could result in de novo syntheses of
Total synthesis of lamellarins D, L, and N
Fujikawa, Naotaka,Ohta, Takeshi,Yamaguchi, Tomohiro,Fukuda, Tsutomu,Ishibashi, Fumito,Iwao, Masatomo
, p. 594 - 604 (2007/10/03)
Total synthesis of cytotoxic marine alkaloids, lamellarins D, L, and N, has been achieved by using Hinsberg-type pyrrole synthesis and palladium-catalyzed Suzuki-Miyaura coupling of the 3,4-dihydroxypyrrole bistriflate 6 as the key reactions. The total yields of lamellarins D, L, and N from the common intermediate 6 are 54, 58, and 50%, respectively.
SELECTIVE DEALKYLATIONS OF ARYL ALKYL ETHERS AND THIOETHERS BY SODIUM IN HMPA
Testaferri, L.,Tiecco, M.,Tingoli, M.,Chianelli, D.,Montanucci, M.
, p. 3687 - 3692 (2007/10/02)
The reaction of sodium with bis- and tris(alkoxy)benzenes in HMPA gives selectively the products of monodealkylation.The reaction proceeds through a dianion which fragments into an alkyl and an aryloxy anion.The positional selectivity of this fragmentation is governed by the structure of both the alkyl and aryloxy groups.With bis- and tris(alkoxy)benzenes which for symmetry reasons can afford aryloxy anions having the same basicity, the dealkylation involves exlusively the less substituted alkyl group.On the contrary, in the asymmetric terms, the positional selectivity of the dealkylation process is governed by the basicity of the aryloxy anion.On the basis of these concepts several efficient and synthetically useful reactions have been developed.In most cases the selectivity obtained in the present reactions in different from that observed with other previously developed methods which use sodium methoxide or sodium alkenethiolates in HMPA.It is shown that the appropriate choice of the reagent allows selective dealkylation of the desired alkoxy group of a poly(alkoxy)benzene.The reaction of sodium with bis(alkylthio)benzenes in HMPA gives the bis(mercapto)benzenes.If the reduction is carried out with a solution of sodium in HMPA, the reaction gives instead the products of monodealkylation.This however is not selective.It is suggested that in the case of thioethers the dealkylation products originate from the fragmentation of the radical anions.
