Synthetic photochemistry. A new synthesis of (±)-zizaene via an intramolecular variant of the de Mayo reaction

Barker, Andrew; Pattenden, Gerald

doi:10.1039/p19830001901

Cited by 28 publications

(19 citation statements)

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“…major product produced from irradiation of the mixture of ( 10) and (11) was indeed the cycloadduct (12) expected from (10) on the basis of the theoretical grounds mentioned earlier.…”

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confidence: 56%

“…In this paper we describe a new approach to the bicyclo[3.2.l]octane ring system which is based on fragmentation of the tricyclo-[3.2.1 .O3s6]octane carbon framework (7)- (8) produced by intramolecular [2 + 21 photocycloaddition of enol acetates derived from 4-prop-2-enylcyclopentane-l,3-diones (6) (Scheme l).' We began our studies of this design to bicyclo[3.2.l]octanes by first investigating the irradiation of the mixture of enol acetates (10) and (1 1) derived from the cyclopentane-1,3dione (9). 4 A priori we might expect to observe the formation of all four cycloadducts (1 2)-( 15) resulting from alternative modes of intramolecular [2 + 21 photocycloaddition in (10) and (1 1).…”

mentioning

confidence: 99%

“…We began our studies of this design to bicyclo[3.2.l]octanes by first investigating the irradiation of the mixture of enol acetates (10) and (1 1) derived from the cyclopentane-1,3dione (9). 4 A priori we might expect to observe the formation of all four cycloadducts (1 2)-( 15) resulting from alternative modes of intramolecular [2 + 21 photocycloaddition in (10) and (1 1). Inspection of a simple electrostatic interaction mechanism for the various cycloadditions leading to (12)-(15), based on the establishment of an initial n-complex between the excited enone chromophores in (10) and (ll), and the alkene,s suggests that the enol acetate (10) would lead preferentially to (12) and that (11) should produce the cycloadduct (15).…”

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confidence: 99%

“…4 A priori we might expect to observe the formation of all four cycloadducts (1 2)-( 15) resulting from alternative modes of intramolecular [2 + 21 photocycloaddition in (10) and (1 1). Inspection of a simple electrostatic interaction mechanism for the various cycloadditions leading to (12)-(15), based on the establishment of an initial n-complex between the excited enone chromophores in (10) and (ll), and the alkene,s suggests that the enol acetate (10) would lead preferentially to (12) and that (11) should produce the cycloadduct (15). Interestingly, the same products are also predicted by frontier orbital theory.6…”

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confidence: 99%

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A new synthetic approach to the bicyclo[3.2.1]octane ring system, based on intramolecular photocycloaddition involving cyclopentane-1,3-dione enol esters

Barker¹,

Begley²,

Mellor³

et al. 1983

J. Chem. Soc., Perkin Trans. 1

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“…major product produced from irradiation of the mixture of ( 10) and (11) was indeed the cycloadduct (12) expected from (10) on the basis of the theoretical grounds mentioned earlier.…”

mentioning

confidence: 56%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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A new synthetic approach to the bicyclo[3.2.1]octane ring system, based on intramolecular photocycloaddition involving cyclopentane-1,3-dione enol esters

Barker¹,

Begley²,

Mellor³

et al. 1983

J. Chem. Soc., Perkin Trans. 1

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“…The power of the de Mayo reaction in natural product synthesis, particularly when operated in the intramolecular mode, has been well exemplified, e.g. in syntheses of loganin,76 longifolene,77 reserpine,78 zizaene79 and hirsutene 80. More recent work by Minter and co‐workers involves an unusual de Mayo reaction developed in an approach toward the galanthan skeleton 95 found in lycorine‐type Amaryllidaceae alkaloids (Scheme ) 81.…”

Section: [2+2] Photocycloadditionmentioning

confidence: 99%

Photocycloaddition in Natural Product Synthesis

2007

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Enone Olefin [2 + 2] Photochemical Cycloadditions

Crimmins

Reinhold

1993

Organic Reactions

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The photochemical [2 + 2] cycloaddition reaction of alkenes to enones, the light‐induced cycloaddition of an excited state enone to a ground state alkene to produce a cyclobutane, is a highly useful reaction in organic synthesis since two new carbon–carbon bonds are formed and a maximum of four new stereogenic centers are introduced into the molecule in the process. The first [2 + 2] photocycloaddition reaction was reported by Ciamician in 1908 when he observed the formation of carvone camphor on exposure of carvone to sunlight for one year. After confirmation of this finding in the late 1950s numerous investigators immediately recognized the value of the reaction for the rapid construction of complex molecular frameworks. The photocycloaddition of a series of Diels–Alder adducts of various dienes and benzoquinones to efficiently produce complex caged structures was subsequently carried out. This included the cycloaddition of a diketone to form a diketone. Meanwhile, a similar photochemical cycloaddition of an enone was utilized in a synthesis of the platonic solid cubane. Shortly thereafter investigations of the intermolecular reaction were initiated through a study of the dimerization of cyclopentenone and the photocycloaddition of cyclopentenone to cyclopentene. Further investigation of the various synthetic and mechanistic aspects of the photocycloaddition resulted in several total syntheses, including caryophyllene and bourbonene, as well as a proposed mechanistic rationale for the reaction. As a result of this pioneering work, largely by Eaton, Corey, and De Mayo, numerous natural and nonnatural products have been prepared by synthetic routes which have a [2 + 2] photocycloaddition as a crucial step in their synthesis. Through further refining over the last 15–20 years, the photocycloaddition reaction has become recognized as an important transformation in the repertoire of the synthetic organic chemist. Both the intermolecular and intramolecular versions of the reaction have been extensively studied. The intramolecular photocycloaddition, like the intramolecular variation of many reactions, has been the subject of much recent work. It is generally thought to be more predictable with regard to regiochemical and stereochemical control, but as will be seen from many of the examples in this chapter, the intermolecular reaction can be highly selective and predictable if the proper reaction participants and conditions are chosen. This chapter reviews the literature on the enone olefin [2 + 2] photocycloaddition since its discovery. Because of the volume of work in the field, there will undoubtedly be some omissions. Examples of all the major types of enone alkene photocycloadditions have been included so that the reader can get a sense of the historical evolution and the current state of the art. Both the inter molecular and the intra molecular variants of this reaction are treated in this chapter. The reader is also referred to a number of excellent reviews on the inter molecular reaction, the intra molecular reaction, and complete treatments which have appeared.

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Synthetic photochemistry. A new synthesis of (±)-zizaene via an intramolecular variant of the de Mayo reaction

Cited by 28 publications

References 6 publications

A new synthetic approach to the bicyclo[3.2.1]octane ring system, based on intramolecular photocycloaddition involving cyclopentane-1,3-dione enol esters

A new synthetic approach to the bicyclo[3.2.1]octane ring system, based on intramolecular photocycloaddition involving cyclopentane-1,3-dione enol esters

Photocycloaddition in Natural Product Synthesis

Enone Olefin [2 + 2] Photochemical Cycloadditions

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