- Modular Construction of Protected 1,2/1,3-Diols, -Amino Alcohols, and -Diamines via Catalytic Asymmetric Dehydrative Allylation: An Application to Synthesis of Sphingosine
-
A new enantioselective catalysis has been developed for the one-step construction of methylene-bridged chiral modules of 1,2- and 1,3-OH and/or NH function(s) from δ- or λ-OH/NHBoc-substituted allylic alcohols and H2C=O / H2C=NBoc . A protonic nucleophile, either in situ-generated CH2OH or CH2NHBoc, is intramolecularly allylated to furnish eight possible 1,2- or 1,3-O,O, -O,N, -N,O, and -N,N chiral modules equipped with an ethenyl group in high yields and enantioselectivities. The utility of this method has been demonstrated in the five-step synthesis of sphingosine.
- Tanaka, Shinji,Gunasekar, Ramachandran,Tanaka, Tatsuya,Iyoda, Yoko,Suzuki, Yusuke,Kitamura, Masato
-
p. 9160 - 9170
(2017/09/11)
-
- Pseudosymmetry in azabicyclo[2.1.1]hexanes. A stereoselective construction of the bicyclic core of peduncularine
-
Intramolecular photocycloaddition of 41 or its equivalent leads to the formation of photoadduct 25. While retro-Mannich fragmentation of the "b" bond in 25 leads to the formation of 44 (via 43), with the incorrect relative stereochemistry for the synthesi
- Ragains, Justin R.,Winkler, Jeffrey D.
-
p. 4437 - 4440
(2007/10/03)
-
- Novel synthesis of [1-11C]γ-vinyl-γ-aminobutyric acid ([1-11C]GVG) for pharmacokinetic studies of addiction treatment
-
γ-Vinyl-γ-aminobutyric acid (GVG, Vigabatrin), a suicide inhibitor of GABA-transaminase (GABA-T), has been suggested as a new drug for the treatment of substance abuse. In order to better understand its pharmacokinetics and potential side effects, we have developed a radiosynthesis of carbon-11 (t1/2=20min) labeled GVG for positron emission tomographic (PET) studies. We report here a novel synthetic strategy to prepare the precursor and to efficiently label GVG with C-11. 5-Bromo-3-(carbobenzyloxy)amino-1-pentene was synthesized in five steps from homoserine lactone, including reduction and methylenation. This was used in a one-pot, two-step radiosynthesis. Displacement of bromide with no-carrier-added [11C]cyanide followed by acid hydrolysis afforded [1-11C]GVG with decay corrected radiochemical yields of 27 ± 9% (n=6, not optimized) with respect to [11C]cyanide in a synthesis time of 45 min. Copyright
- Zhang, Zongren,Ding, Yu-Shin,Studenov, Andrei R.,Gerasimov, Madina R.,Ferrieri, Richard A.
-
p. 199 - 211
(2007/10/03)
-
- Pronounced electronic effect of allylic amino groups on the π-facial stereoselectivity and reactivity of the iodoetherification of N-substituted 3-amino-4-penten-1-ols
-
The iodoetherification of N-substituted 3-amino-4-penten-1-ol (1) [I2 and NaHCO3 (2 equivalents each) in ether/H2O at 0°C], providing the mixtures of N-substituted cis- and trans-3-amino-2-iodomethyltetrahydrofurans (9), d
- Tamaru, Yoshinao,Harayama, Hiroto,Bando, Takashi,Nagaoka, Hirooki,Yoshida, Zen-Ichi
-
p. 223 - 234
(2007/10/03)
-