103957-83-1Relevant articles and documents
Unified enantioselective total syntheses of (?)-scholarisine G, (+)-melodinine E, (?)-leuconoxine and (?)-mersicarpine
Liu, Yao,Wang, Honggen
, p. 3544 - 3547 (2019)
A unified strategy enabled the enantioselective syntheses of (?)-scholarisine G, (+)-melodinine E, (?)-leuconoxine and (?)-mersicarpine from a common 2-alkylated indole intermediate bearing an all-carbon quaternary stereogenic center. The Smith-modified Madelung indole synthesis was used to couple simple o-toluidine with chiral lactone (+)-8, incorporating the key elements for further cyclizations. Lactone (+)-8 was prepared via a palladium-catalyzed intermolecular asymmetric allylic alkylation. The unified and protecting-group-free reaction sequences allowed the synthesis of these alkaloids in a maximum of 10 steps and with high efficiency.
A photochemical route to carbapenems from pyrazolidin-3-ones. Formal synthesis of PS-5
White, James D.,Toske, Steven G.
, p. 207 - 210 (1993)
Photochemical ring contraction of a cis disubstituted pyrazolidin-3-one, prepared by hydrazinolysis of an α,β-unsaturated δ-lactone, gave the corresponding azetidinone which has been converted previously to the carbapenem antibiotic PS-5.
Asymmetric Total Synthesis of Kopsiyunnanine K, a Monoterpenoid Indole Alkaloid with a Rearranged Skeleton
Tokuda, Ryoko,Okamoto, Yoshiki,Koyama, Tetsuya,Kogure, Noriyuki,Kitajima, Mariko,Takayama, Hiromitsu
, p. 3490 - 3493 (2016)
A new monoterpenoid indole alkaloid, kopsiyunnanine K, was isolated from Kopsia arborea. Its intriguing rearranged structure and absolute configuration, which were inferred from spectral data and a possible biosynthetic pathway, were determined on the bas
Enantioselective Construction of Quaternary Carbon Stereocenter via Palladium-Catalyzed Asymmetric Allylic Alkylation of Lactones
Li, Xiao-Hui,Wan, Shi-Li,Chen, Di,Liu, Qing Rong,Ding, Chang-Hua,Fang, Ping,Hou, Xue-Long
supporting information, p. 1568 - 1572 (2016/05/24)
An efficient and practical method for the synthesis of α,α-disubstituted six-membered lactones was developed. Enantioselective construction of quaternary carbon centers by utilizing Pd-catalyzed asymmetric allylic alkylation proved its feasibility.
Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
, p. 10609 - 10616 (2012/11/07)
α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
Branched-regioselective hydroformylation with catalytic amounts of a reversibly bound directing group
Gruenanger, Christian U.,Breit, Bernhard
supporting information; experimental part, p. 7346 - 7349 (2009/04/07)
(Chemical Equation Presented) Phosphinites do the trick and work as reversibly bound catalyst-directing groups in catalytic amounts to allow for the highly regioselective hydroformylation of homo-allylic alcohols with terminal and internal alkene functions in favor of the branched product.
Novel photolactonisation from xanthenoic esters
Plessis, Caroline,Derrer, Sam
, p. 6519 - 6522 (2007/10/03)
In the context of our work on photocleavable fragrance precursors, we have discovered a new photo-fragmentation of xanthenoic esters into xanthene- and formyl radicals. This homolytic cleavage has not been reported previously. Thus, unsaturated formyl radicals cyclise to lactones of various ring size.
Enantioselective synthesis of 2-substituted 6- and 7-membered lactones via α-alkylation of lactone hydrazones
Enders,Grobner,Runsink
, p. 947 - 951 (2007/10/02)
2-Alkyl-substituted lactones 4 were synthesized in good overall yields and high enantiomeric purities (ee = 90-94%) by deprotonation and alkylation of the corresponding lactone SAMP-hydrazones 2 and subsequent oxidative cleavage of the product hydrazones 3 by ozonolysis. The lactone hydrazones 2, in turn, were prepared in good yields by silver promoted cyclization of ω-chloroalkanohydrazides 1.
Synthesis of γ- and δ-Lactones by Free-Radical Annelation of Se-Phenyl Selenocarbonates
Bachi, Mario D.,Bosch, Eric
, p. 4696 - 4705 (2007/10/02)
A general method for the synthesis of γ- and δ-lactones through the intramolecular addition of alkoxycarbonyl radicals, formed by reaction of Se-phenylselenocarbonates with n-Bu3SnH, onto carbon-carbon multiple bonds is described.This free-radical cyclization is characterized by high regioselectivity favoring exo addition and by a high ratio of cyclization to reduction.Monocyclic, fused bicyclic, and spirocyclic lactones are formed in good to excellent yield.Use of allyltri-n-butyltin as a chain-transfer agent in the place of n-Bu3SnH affords the corresponding 3-butenyl lactones.
