Enantiocontrolled construction of bicyclic proline derivatives via one-pot generation and intramolecular trapping of chiral stabilised azomethine ylids
摘要:
Aldehydes possessing unsaturation at C-5 or C-6 condense with (5S)-phenylmorpholin-2-one (1), generating chiral stabilised azomethine ylids which undergo concommitant diastereospecific intramolecular 3+2 dipolar cycloaddition to furnish adducts (2), (4), and (5) which may be converted to homochiral bicyclic proline derivatives. Reductive desulfurisation of the thioether derivative (5) leads to (2S,4R,5R)-4,5-dimethylproline (7).
Intramolecular Alkene Aminocarbonylation Using Concerted Cycloadditions of Amino-Isocyanates
作者:Ryan A. Ivanovich、Christian Clavette、Jean-François Vincent-Rocan、Jean-Grégoire Roveda、Serge I. Gorelsky、André M. Beauchemin
DOI:10.1002/chem.201600574
日期:2016.6.1
temperatures (150–200 °C), and issues included competing hydroamination and N‐isocyanate dimerization pathways. Herein, improved conditions for concerted intramolecular alkene aminocarbonylation with N‐isocyanates are reported. The use of βN‐benzyl carbazate precursors allows the effective minimization of N‐isocyanate dimerization. Diminished dimerization leads to higher yields of alkene aminocarbonylation
X=Y-ZH systems as potential 1,3-dipoles. Part 31. Generation of nitrones from oximes. Background and scope of the tandem 1,2-prototropy-intramolecular cycloaddition sequence.
作者:Ronald Grigg、Frances Heaney、Jasothara Markandu、Sivagnanasundram Surendrakumar、Thornton-Pett Mark、Warnock J. William
DOI:10.1016/s0040-4020(01)86441-3
日期:1991.1
and electronic factors that favour or disfavour such a sequence are discussed. Deuterium labelling studies with an aliphatic oxime rule out the involvement of an enehydroxylamine in the prototropic generation of the NH nitrone.
Diastereoselektive Synthese von α,γ-Aminoalkoholen durch intramolekulare 1,3-dipolare Cycloaddition von Nitronen mit Allylthioether-Gruppierung und anschließende reduzierende Ringöffnung
作者:Hans Günter Aurich、Klaus-Dieter Möbus
DOI:10.1016/s0040-4039(00)82182-6
日期:1988.1
The bicyclic compounds 2 and 4 are formed by intramolecular 1,3-dipolar cycloaddition of the nitrones 1 and 3, respectively. Reductive cleavage of 2a and 4a with desulfurization yields α,γ-aminoalcohols 7 and 9, respectively, as diastereomerically pure compounds.
Aurich, Hans Guenter; Boutahar, Mostafa; Koester, Heiner, Chemische Berichte, 1990, vol. 123, # 10, p. 1999 - 2014
作者:Aurich, Hans Guenter、Boutahar, Mostafa、Koester, Heiner、Moebus, Klaus-Dieter、Ruiz, Luis
DOI:——
日期:——
Bidirectional Synthesis of the IJK Fragment of Ciguatoxin CTX3C by Sequential Double Ring-Closing Metathesis and Tsuji–Trost Allylation
作者:Michael Popadynec、Helen Gibbard、J. Stephen Clark
DOI:10.1021/acs.orglett.0c01238
日期:2020.5.1
A novel four-step bidirectional strategy has been used to synthesize the IJK fragment of the marine polyether natural product CTX3C from a simple monocyclic precursor in a concise and efficient manner. The four-step bidirectional sequence involves ring-closing metathesis, alcohol oxidation, enol carbonate formation, and palladium-mediated Tsuji-Trost allylation.