Reversed Stereochemical Course of the Michael Addition of Cyclohexanone to β‐Nitrostyrenes by Using 1‐(Trimethylsiloxy)cyclohexene/Dichloro(diisopropoxy)titanium. Preliminary Communication

doi:10.1002/HLCA.19850680205

Paper

Reversed Stereochemical Course of the Michael Addition of Cyclohexanone to β‐Nitrostyrenes by Using 1‐(Trimethylsiloxy)cyclohexene/Dichloro(diisopropoxy)titanium. Preliminary Communication

Published Mar 27, 1985 · D. Seebach, M. Brook

Helvetica Chimica Acta

Q2 SJR score

46

Citations

0

Influential Citations

Full textSemantic Scholar

Abstract

Induced by a stoichiometric excess of dichloro(diisopropoxy)titanium, 1-(trimethylsiloxy)cyclohexene and p-substituted β-nitrostyrenes (Y = H,CH3,CH3O,CN) combine in CH2Cl2 solution at −90° preferentially with relative topicity ul – opposite to the corresponding reaction of enolates or enamines. The primary products are the bicyclic nitronates 3–5 which can be separated, and which are cleaved by KF in MeOH to give the aryl(nitroethyl)-substituted cyclohexanones 1 and 2 (Tables 1 and 2, two typical procedures are given). The major products (2:1 to 4:1) are the hitherto not readily available diastereoisomers 2 of l-configuration. Instead of being solvolyzed, the bicyclic nitronate 5 can be used for nitroaldol additions (6) and for [3 + 2]-dipolar cycloadditions (7), diastereoselectively furnishing products with 4 asymmetric C-atoms (not counting acetal centers). The Michael addition described here is yet another example of an ul-combination of trigonal centers induced by Lewis acids, overriding the influence of the configuration of the donor component.

Study Snapshot

The Michael addition of cyclohexanone to -nitrostyrenes using 1-(trimethylsiloxy)cyclohexene/dichloro(diisopropoxy)titanium produces diastereoisomers with l-configuration, demonstrating

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Sign up to use Study Snapshot

Consensus is limited without an account. Create an account or sign in to get more searches and use the Study Snapshot.

Create an account

Paper

Reversed Stereochemical Course of the Michael Addition of Cyclohexanone to β‐Nitrostyrenes by Using 1‐(Trimethylsiloxy)cyclohexene/Dichloro(diisopropoxy)titanium. Preliminary Communication

Sign up to use Study Snapshot

References

Über den sterischen Verlauf der Umsetzung von Enaminen aus offenkettigen Aldehyden und Ketonen mit Nitroolefinen zu 2,3‐disubstituierten 4‐Nitroketonen

Enamines from open-chain aldehydes and ketones react with nitro-olefins to produce 2,3-disubstituted 4-nitroketones, confirming the stereochemical course predicted by our topological rule.

Asymmetrische Michael‐Additionen. Regio‐, diastereo‐ und enantioselektive Alkylierungen der Enamine aus β‐Tetralonen und (S)‐2‐(Methoxymethyl)pyrrolidin („Prolinolmethylether”︁) durch ω‐Nitrostyrole

This study demonstrates that asymmetric Michael additions can produce highly diastereomeric and optically pure enamines from -tetralones and (S)-2-(Methoxymethyl)pyrrolidine, with products having a (3S, 1′R)-configuration.

Asymmetrische Michael‐Additionen. Stereoselektive Alkylierungen des (R)‐ und (S)‐Enamins aus Cyclohexanon und 2‐(Methoxymethyl)pyrrolidin durch α‐(Methoxycarbonyl)zimtsäure‐methylester

This study presents a highly effective asymmetric synthesis method for enamines from cyclohexanone and 2-(methoxymethyl)pyrrolidine, yielding 35-76% of adducts with > 90% diastereomeric purity and 80% enantiomeric excess.

From crystal statics to chemical dynamics

The crystal structure of senkirkine, ClsHnN06, reveals a correlation between bond number and carbonyl peak frequency in the infrared spectrum, potentially impacting methadone's physiological activity.

The Unambiguous Specification of the Steric Course of Asymmetric Syntheses

This paper proposes a method for unambiguous specification of the steric course and product configuration of diastereoselective reactions, enabling more precise stereoselective synthesis of complex natural products.

Citations

Construction of Saturated Oxazolo[3,2-b][1,2]oxazines via Tandem [3+2]-Cycloaddition/[1,3]-Rearrangement of Cyclic Nitronates and Ketenes.

Saturated oxazolo[3,2-b][1,2]oxazines can be synthesized by reacting six-membered cyclic nitronates with disubstituted ketenes, offering potential as precursors for other fused 1,2-oxa

Molecular mechanism of Hetero Diels-Alder reactions between (E)-1,1,1-trifluoro-3-nitrobut-2-enes and enamine systems in the light of Molecular Electron Density Theory.

The molecular mechanism of Hetero Diels-Alder reactions between (E)-1,1,1-trifluoro-3-nitrobut-2-enes and enamine systems involves formation of zwitterionic structures in the first reaction stage, followed by three stages of bond breaks, pseudoradical

Stoichiometric Reactions of Enamines Derived from Diphenylprolinol Silyl Ethers with Nitro Olefins and Lessons for the Corresponding Organocatalytic Conversions – a Survey

Stoichiometric reactions of enamines from diphenyl-prolinol silyl ethers with nitro olefins reveal insights into organocatalytic reactions and their limitations.

Lewis Acid‐Mediated Addition of Amino Acid‐Substituted α‐Allylsilanes to Aromatic Acetals

Using TiCl4 as the most effective Lewis acid, we can efficiently prepare unnatural amino acid derivatives with high selectivity and yield.

β-Nitroacrylates and silyl enol ethers as key starting materials for the synthesis of polyfunctionalized β-nitro esters and 1,2-oxazine-2-oxides

-Nitroacrylates and silyl enol ethers can be used to synthesize polyfunctionalized -nitro esters and 1,2-oxazine-2-oxides, depending on the starting silyl enol ethers.

Diversity-Oriented Synthesis of Functionalized 1-Aminopyrroles by Regioselective Zinc Chloride-Catalyzed, One-Pot ‘Conjugate Addition/Cyclization’ Reactions of 1,3-Bis(silyl enol ethers) with 1,2-Diaza-1,3-butadienes

This one-pot process allows for the synthesis of functionalized 1-aminopyrroles and 1-amino-4,5,6,7-tetrahydroindoles, offering a new approach for diverse synthesis of organic compounds.