Intramolecular Interaction of Cyclopropylidene with the Bicyclo[1.1.0]butane System

Christl, Manfred; Lechner, Monika

doi:10.1002/anie.197507652

Cited by 5 publications

(1 citation statement)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Diels-Alder reaction of 99 and its analogues with dienes such as furan73 and benzindole74 derivatives provides a useful route to small-ring propellanes75 containing the bicyclobutane moiety.76 Due to the extreme susceptibility of the double bond of 99 and its analogues to undergo nucleophilic addition, it is possible to introduce bridgehead substitution in the bicyclobutane.77,78 Use of sterically hindered nonnucleophilic bases67,73,79 allows the introduction of thio and amino groups into the bridgehead position of the molecule. 76,80 n-Butylmethylquadricyclanes 108 and 109 were isolated by Szeimes and co-workers in a 2:1 ratio when a mixture of 1-chloroquadricyclane (107) and n-butyllithium was quenched with methyl bromide (Scheme 23)81,82 The mixture of 108 and 109 was then thermally converted to norbornadienes 110 and 111. Tetracyclo[3.2.0.02,7.04,6]hept-l(7)-ene (112), a derivative of 94, was proposed as a reactive intermediate, formed by an elimination process analogous to the one described above for 99.…”

Section: Ch Mementioning

confidence: 99%

Bicyclo[n.1.0]alkenes

Billups¹,

Haley²,

Lee³

1989

Chem. Rev.

View full text Add to dashboard Cite

Section: Ch Mementioning

confidence: 99%

Bicyclo[n.1.0]alkenes

Billups¹,

Haley²,

Lee³

1989

Chem. Rev.

View full text Add to dashboard Cite

The IntramolecularDiels–Alder Reaction

Ciganek

1984

Organic Reactions

108

View full text Add to dashboard Cite

The Diels–Alder reaction is one of the most useful reactions available to the synthetic organic chemist. It is thus surprising that the intramolecular version, in which both diene and dienophile are part of the same molecule, remained virtually unexplored for many years. Early examples were often the result of unexpected observations, and the many advantages of this reaction were recognized and put to use in the synthesis of complex polycyclic molecules only recently. In the intramolecular Diels–Alder reaction, two rings are formed in one step. In addition to the six‐membered ring formed by the [4 + 2]cycloaddition, the product contains a second ring, the size of which depends on the length of the chain connecting diene and dienophile. Of the two possible regiochemical modes of addition, that leading to the fused product usually predominates to the virtual exclusion of the bridged product. The Diels–Alder reaction proceeds through a highly ordered transition state that is reflected in large negative activation entropies. In the intramolecular version, some of the ordering has been accomplished in advance by making the two reacting functionalities part of the same molecule. This results in less negative activation entropies and increased reaction rates under often surprisingly mild conditions. On the other hand, by using forcing conditions one can sometimes carry out intramolecular Diels–Alder additions that would be doomed to failure in the intermolecular version. Lower reaction temperatures, together with the constraints imposed by the connecting chain, often result in pronounced regio‐ and stereoselectivity. Side reactions such as dimerization or polymerization can be avoided by using high dilution or low pressures in the gas phase. Examples where the bimolecular Diels–Alder reaction interferes with the intramolecular cyclization are rare. All of these features suggest that the intramolecular Diels–Alder reaction should be considered for any synthesis of a molecule containing a six‐membered ring fused to a second ring, especially if that ring is five‐ or six‐membered. Such a synthetic scheme may be made convergent by building up the diene and dienophile portions separately and connecting them just prior to the actual cyclization. Another potential use of the intramolecular Diels–Alder reaction that has not received much attention to date is as a supplement to the intermolecular Diels–Alder reaction in cases where the latter is unsuccessful or gives the wrong regio‐ or stereochemistry. By judicious choice of the connecting chain, the reaction may be made to proceed with the desired selectivity; this is followed by cleavage of the chain and conversion of the two ends to the desired functionalities. Once the feasibility of employing the intramolecular Diels–Alder reaction has been recognized, the main challenge often becomes the preparation of the substrate. A discussion of that aspect is beyond the scope of this chapter; however, by scanning the tables for the particular diene, dienophile, and chain one is interested in, and then referring to the original literature, it will often be possible to obtain some indications on how to proceed. An attempt has been made to cover the literature of the thermal intramolecular Diels–Alder reaction as completely as possible up to and including the year 1981. Many of the papers that appeared in 1982 and some from 1983 have also been included. More recent references are given in an addendum at the end of the tabular survey.

show abstract

1,6‐Dimethyltricyclo[4.1.0.0 ^1,6 ]hept‐3‐ene

Taylor

Paquette

2003

Organic Syntheses

View full text Add to dashboard Cite

1,6‐Dimethyltricyclo[4.1.0.0 1,6 ]hept‐3‐ene solvent: 1 L of olefin‐free petroleum ether product: 1,6‐Dimethyltricyclo[4,1.0.02,7]hept‐3‐ene. intermediate: 20.95 g (0.075 mol) of 7,7‐dibromo‐1,6‐dimethylbicyclo[4.1.0]hept‐3‐ene

show abstract

Intramolecular Interaction of Cyclopropylidene with the Bicyclo[1.1.0]butane System

Cited by 5 publications

References 11 publications

Bicyclo[n.1.0]alkenes

Bicyclo[n.1.0]alkenes

The IntramolecularDiels–Alder Reaction

1,6‐Dimethyltricyclo[4.1.0.0 ^1,6 ]hept‐3‐ene

Contact Info

Product

Resources

About