Ground-State and Photochemical Reactions in the Epoxypyrone Series<sup>1-3</sup>

Padwa, Albert; Hartman, R. J.

doi:10.1021/ja00968a015

Cited by 31 publications

(13 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Not unexpectedly, the dichlorocarbene adduct 4b of 9-methoxyphenanthrene reacted with base uiu elimination of HCI to 5d and, finally, to phenanthro[9,10-b]furan (17) [16] [17] by the sequence outlined in Scheme 4 which is formulated in analogy to the behavior of 5b [9]. Intermolecular insertion of a chlorocarbene into a C-H bond adjacent to an ether function has been reported for chloro-9-phenanthryl carbene, where intramolecular insertion is impossible [9] [ 1 11.…”

Section: Scheme 4 4b 5dmentioning

confidence: 99%

Approaches to 1H‐Cyclopropa[l]phenanthrenes. Eliminations with 1a,9b‐Dihydro‐1H‐cyclopropa[l]phenanthrene Derivatives

Müller¹,

Thi²,

Pfyffer³

1986

Helvetica Chimica Acta

View full text Add to dashboard Cite

Base-induced elimination of the sulfonium salt 2i in the presence of furan affords the addition products 7 and 8, derived from 1H-cyclopropa[l]phenanthrene (1) and the isomeric cyclopropene 5a (Scheme 3). Upon oxidation, the selenide 2c yields phenanthrene-9-methanol (9), presumably via 1. No evidence for the intermediate 1 is obtained from sulfoxide pyrolysis with 2e, which leads to products formed by radical pathways (Scheme 5 ) . Reductive elimination of the disulfone 3b gives half-reduction to monosulfone 2g and complete reduction to cyclopropane 2 as well as 9methylphenanthrene (IS), but no evidence for the intermediate 1. Scheme I2 1 3 Substituted la,9b-Dihydro-lH-cyclopropa[l]phenanthrenes. -Compounds of structure 2 are in principle available via carbene addition to 9-substituted phenanthrenes [3] [6]. This approach was attempted, but abandoned when it was found impossible to effect dichlorocarbene addition to 9-bromophenanthrene under a variety of conditions. Similarly, the cyclopropan-forming procedure using diazomethane/CuBr which works for phenanthrene [7] afforded no addition product with the 9-bromo derivative. Alternatively, base-induced elimination of 1-halogenated dihydrocyclopropa[l]phenanthrenes in the presence of nucleophiles was investigated. Reaction of the dichlorocarbene adduct 4 [S] of phenanthrene with base in the presence of methanethiolate is known to afford the H E L~T I C A CHIMICA ACTA -Vol. 69 (1 986) Scheme 2 4 CI

show abstract

Section: Scheme 4 4b 5dmentioning

confidence: 99%

Approaches to 1H‐Cyclopropa[l]phenanthrenes. Eliminations with 1a,9b‐Dihydro‐1H‐cyclopropa[l]phenanthrene Derivatives

Müller¹,

Thi²,

Pfyffer³

1986

Helvetica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…The principal methods for the synthesis of 1,3-teraryls are largely based on the metal-assisted, 8 aryllithium 9 and arylboric acid 10 arylation of 1,3-dihalobenzene, decomposition 11 of 3-(nitrosoacetamido)biphenyls or 1,3-bis(nitrosoacetamido)benzene, and the action of arylmagnesium halides on 3-pheenylcyclohexanone, 12 alkyl 3chlorophenyl sulfides, 13 and 4,6-diarylpyran-2-ones 14 separately. The Diels-Alder reaction of the latter with methyl propiolate 15 also led to the formation of the title compound. A circuitous multistep synthesis 16 of 1,3-teraryls has also been reported in poor yield.…”

mentioning

confidence: 99%

Synthesis of 1,3-Teraryls Through Carbanion Induced Ring Transformation of Functionalised Pyran-2-ones

Goel¹,

Srivastava²,

Nath³

et al. 1998

Synthesis

View full text Add to dashboard Cite

1,3-Teraryls 2 were synthesised by reaction of 6-aryl-3-methoxycarbonyl-4-(methylthio)-2H-pyran-2-ones 1a with aryl methyl ketones. An analogous reaction with 6-aryl-3-cyano-4-(methylthio)-2H-pyran-2-ones 1b and aryl methyl ketones failed to yield cyano-substituted 1,3-teraryls, but afforded (4,6-diarylpyran-2-ylidene)acetonitriles 4 in poor yields.The marvel of the specificity in biological systems of recognising tailor-made synthetic molecules which imitate the working features of naturally occurring compounds led to the design and synthesis of molecular hosts, guests and their complexes. Recently, the chemistry of synthetic hosts for selective complexation has received extraordinary attention 1,2 due to their pharmacological potential as carriers of ions and molecules. The presence of specific cavities in the molecular makeup of host molecules is responsible for the molecular recognition resulting in the desired bioresponses. Here, we address our synthetic efforts towards functionalised symmetrical and unsymmetrical 1,3-teraryls as intermediates for the synthesis of host compounds 3-7 in a single step through ring-transformation reactions.The principal methods for the synthesis of 1,3-teraryls are largely based on the metal-assisted, 8 aryllithium 9 and arylboric acid 10 arylation of 1,3-dihalobenzene, decomposition 11 of 3-(nitrosoacetamido)biphenyls or 1,3-bis(nitrosoacetamido)benzene, and the action of arylmagnesium halides on 3-pheenylcyclohexanone, 12 alkyl 3-chlorophenyl sulfides, 13 and 4,6-diarylpyran-2-ones 14 separately. The Diels-Alder reaction of the latter with methyl propiolate 15 also led to the formation of the title compound. A circuitous multistep synthesis 16 of 1,3-teraryls has also been reported in poor yield. Our approach to synthesise 1,3-teraryls is based on the carbanion induced ring transformation of 6-aryl-3-methoxycarbonyl-4-(methylthio)-2H-pyran-2-ones 17 1a. However, the symmetrical 1,3-teraryls were also obtained directly as a side product from the reaction of methyl 2-methoxycarbonyl-3,3-bis(methylthio)acrylate with aryl methyl ketones, possibly through the intermediacy of pyran-2-ones 1a. To establish the course of the reaction, an independent reaction of 1a with aryl methyl ketones was carried out which resulted in the formation of the respective 1,3-teraryls. However, under similar reaction conditions, reaction of aryl methyl ketones with 6-aryl-3-cyano-4-(methylthio)-2H-pyran-2-ones 1b yielded 4, a minor product analogous to 3, through an enolised intermediate and a decomposed material as a major constituent. 6-Aryl-3-methoxycarbonyl-4-(methylthio)-2H-pyran-2-ones 1a and 6-aryl-3-cyano-4-(methylthio)-2H-pyran-2-ones 1b used as precursors were synthesised by basecatalysed condensation-cyclization of aryl methyl ketones with methyl 2-methoxycarbonyl-3,3-bis(methylthio)acry 1 late 18 and ethyl 2-cyano-3,3-bis(methylthio)-acrylate, 8 respectively. During the synthesis of 1a, a new minor product was also isolated and characterised as the 1,3-teraryl 2 (Scheme 1). The formation of...

show abstract

“…However, from the reaction of the salt ( 2 c ) the bis-Wittig product (6) was also obtained, but in very low yield. On the other hand, reactions of 1,6and 1,5-bisphosphonium salts (18) and (26) with o-quinones (1), (20), and (21) resulted in the formation of 9-(0-hydroxyary1)phenanthrenes ( 22)-( 24) and 1 -(o-hydroxyary1)acenaphthylenes ( 28) and (29). Reaction mechanisms involving initial Wittig reaction of one carbonyl group with one ylide group are proposed.…”

mentioning

confidence: 99%

Reactions of o-quinones with some bis-phosphonium salts in the presence of lithium ethoxide

Litinas¹,

Nicolaides²

1985

J. Chem. Soc., Perkin Trans. 1

View full text Add to dashboard Cite

Ground-State and Photochemical Reactions in the Epoxypyrone Series^1-3

Cited by 31 publications

References 3 publications

Approaches to 1H‐Cyclopropa[l]phenanthrenes. Eliminations with 1a,9b‐Dihydro‐1H‐cyclopropa[l]phenanthrene Derivatives

Approaches to 1H‐Cyclopropa[l]phenanthrenes. Eliminations with 1a,9b‐Dihydro‐1H‐cyclopropa[l]phenanthrene Derivatives

Synthesis of 1,3-Teraryls Through Carbanion Induced Ring Transformation of Functionalised Pyran-2-ones

Reactions of o-quinones with some bis-phosphonium salts in the presence of lithium ethoxide

Contact Info

Product

Resources

About

Ground-State and Photochemical Reactions in the Epoxypyrone Series1-3

Cited by 31 publications

References 3 publications

Approaches to 1H‐Cyclopropa[l]phenanthrenes. Eliminations with 1a,9b‐Dihydro‐1H‐cyclopropa[l]phenanthrene Derivatives

Approaches to 1H‐Cyclopropa[l]phenanthrenes. Eliminations with 1a,9b‐Dihydro‐1H‐cyclopropa[l]phenanthrene Derivatives

Synthesis of 1,3-Teraryls Through Carbanion Induced Ring Transformation of Functionalised Pyran-2-ones

Reactions of o-quinones with some bis-phosphonium salts in the presence of lithium ethoxide

Contact Info

Product

Resources

About

Ground-State and Photochemical Reactions in the Epoxypyrone Series^1-3