59627-58-6

Upstream product

• 133620-92-5 (6-Bromo-4-methoxy-2-methylene-hexylsulfanyl)-benzene 
• 29882-07-3 4-chlorobutanal dimethyl acetal 
• 77192-17-7 dimethyl 2-(4,4-dimethoxybutyl)-2-(prop-2-ynyl) malonate 
• 77192-19-9 1,1-dimethoxy-5-(chloromethyl)-hex-5-ene 
• 77192-18-8 6,6-dimethoxy-2-hydroxymethylhex-1-ene 
• 91988-32-8 4-iodobutyraldehyde dimethyl acetal 
• 155623-51-1 Methanesulfonic acid 4-trimethylsilanylmethyl-pent-4-enyl ester 
• 139929-54-7 4-trimethylsilyl-1-iodo-4-pentene 
• 99667-09-1 4-((trimethylsilyl)methyl)pent-4-en-1-ol 
• 155623-52-2 1-methoxy-5-trimethylsilylmethyl-5-hexen-1-yl-phenyl sulfone 
• 59627-56-4 [2-(4,4-dimethoxybutyl)-2-propenyl]trimethylsilane 
• 33979-00-9 6,6-dimethoxy-2-methyl-hex-1-ene 
• 67-56-1 methanol 
• 65513-21-5 tricyclo[3.1.1.0^1,5]heptane 

Relevant academic research and scientific papers

Selectivity of bifunctional annulating reagents: Additional rules for ring closure

From a consideration of the products of cyclisation of allyisilanes it is concluded that stereoelectronic effects play a dominant role and that descriptors, similar to those for predicting intramolecular aldol cyclisations, could be used for intramolecular cyclisations of allylic species.

Annulation Based on 6-Endo-Trig Radical Cyclization: Regioselectivity and Diastereoselectivity

The development of a annulation strategy based on sequential "two-electron" and "one-electron" allylation of β-substituted aldehydes and derivatives with the bifunctional isobutene conjunctive reagent 1 is described.The key step involves an unusual 6-endo-trig radical cyclization.Yields of 6-endo products are improved if the PhS group is oxidized to a PhSO2 group prior to cyclization.The structural factors affecting the regioselectivity and stereoselectivity of the cyclization are examined.In general, the stereoselectivity of 6-endo-trig cyclization of 5-hexenyl radicals can be rationalized by conformational analysis of chairlike transition states and can be calculated effectively with an MM2 force field model.High 6-endo regioselectivity requires a strong driving force.Fragmentable allylic groups (R3Sn, PhSO2, and to a lesser extent PhS) are shown to be sufficiently activating to achieve 6-endo regioselectivity.

Bridgehead Carbocations: Solvolysis of a Series of 5-Substituted Bicycloheptyl Bromides. Nucleophilic Solvent Assistance to Ionization of 1-Bromobicycloheptane

The synthesis of a range of 5-substituted bicycloheptyl bromides for solvolytic studies is described.It is found that the substituent has a profound effect on the rate of solvolysis of the system and acts principally in accordance with the magnitude of its inductive/field constant ?I.The most spectacular example of the effect of the substituent is provided by the COOMe group which leads to a retardation in the rate of methanolysis by a factor of 6.5E5.While a linear relationship in the plot of log k and ?I is generally obeyed, as expected for a mechanism mediated by the bicycloheptyl bridgehead cation, two of the bromides, 1-bromobicycloheptane and its 5-methoxy derivative, show deviant behaviour and react more rapidly than predicted on the basis of the Hammett plot.Evidence is presented to show that the enhanced rate of the parent is the result of nucleophilic assistance by the solvent.Anchimeric assistance in the solvolysis of 5-methoxybicycloheptyl bromide is attributed to the powerful p-donor property of the methoxy substituent which stabilizes the transition state in a unique concerted ring-opening and ionization step.

Towards the Synthesis of the C37-C42 Fragment of Rapamycin: Intramolecular Reactions of Allyl Silanes with Oxonium Ions Generated from α-Alkoxy Sulfones.

A new method for the formation of methylene cyclohexane derivatives has been developed, using intramolecular trapping by allyl silanes of oxonium ions generated from α-alkoxysulfones.These acyclic precursors were prepared by quenching the anion of methoxy

[3+3] Annulation by sequential two electron and one electron allylation

3-phenylthio-2-(trimethylsilymethyl)propene is a convenient conjunctive reagent for the preparation of methylenecyclohexanes via a [3+3] annulation. The trimethylsilyl group facilitates the Lewis acid catalyzed allylation of an aldehyde or acetal while the phenylthio group directs a 6-endo-trig radical cyclization reaction.

THROUGH-SPACE EFFECTS OF SUBSTITUENTS ON THE STABILITY OF THE 1-BICYCLOHEPTYL CATION.

γ-Substituents are shown to have a dramatic effect on the stabilisation of the cationic transition state for solvolysis of 5-substituted bicycloheptyl bromides.

Enhanced Solvolytic Reactivity of 1-Bromobicycloheptane: Intermediacy of a Stabilised Bridgehead Carbenium Ion

1-Bromobicycloheptane displays greater solvolytic reactivity than t-butyl bromide and produces a bridgehead carbenium ion which appears to be stabilised by transannular orbital interactions.

Controlling the Outcome of a Carbocation-Initiated Cyclisation

The allylsilane, 6,6-dimethoxy-2-(trimethylsilylmethyl)hex-1-ene (2) gives 3-methylenecyclohexyl methyl ether (7) on treatment with tin (IV) chloride, whereas cyclisation of the corresponding compound without the silyl group (1) was known to give five products (5)-(6).The synthesis of the allylsilane (2) is described.