Mercury-photosensitized reactions of 1,4-dienes

Meinwald, Jerrold; Smith, Grant W.

doi:10.1021/ja00995a017

Cited by 18 publications

(8 citation statements)

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“…Between the g.c. peaks due to (10) and (11) [both of which appear soon after that due to (9)] was a minor peak due to a compound which we tentatively identify as the silacyclopentane (12) on the basis of its mass spectrum, m/e 156 ([MI+, 15"/,), 141 (6), 129 (19), 128 (loo), 114 (13), 113 ( 8 9 , 99 (23), 88 (9, 87 (23), 86 (99, 85 (12), 73 (38), 72 (6), 71 (6), 70 (9, 69 (3, 60 (6), 59 (56), 58 (77), 55 (15), and 53 ( 5 ) ; the [M + 1]+ and [M + 2]+ ions have the expected intensity relative to the [MI+ ion). The yield of (12) was 0.01 mmoles.…”

Section: Methodsmentioning

confidence: 91%

“…The separated organic layer was washed with water and dried (MgS04). After solvent evaporation and distillation the desired silane (9) (5.2 g) was (6), 100 (lo), 99 (4), 87 (28), 85 (7), 73 (12), 72 (7), 69 (4), 60 (7), and 59 (100).…”

Section: Methodsmentioning

confidence: 99%

“…peaks appeared shortly before the peak due to (10). The first, and by far the larger of these two peaks, was identified as the silacyclohexene (1 1) by its mass spectrum, m/e 154 ([MI+, 26%) 140 (8), 139 (56), 127 (12), 126 (lo), 112 (16), 11 1 (87), 109 (1 l), 99 (17), 98 (3, 97 (17), 95 (13), 85 (13), 83 (19), 81 (6), 79 (7), 74 (7), 73 (71), 72 (9), 71 (7), 69 (9), 67 (9), 59 (56), 58 (13), 55 (15), and 53 (11). Between the g.c.…”

Section: Methodsmentioning

confidence: 99%

“…At lower temperatures there may be some intermolecular addition. duct (12) was only tentatively identified. If produced, it is formed in only 1% yield.…”

mentioning

confidence: 99%

“…by only two out of its * N.6. The chloroplatinic acid catalysed cyclization of silanes which are structurally analogous to (1 8) favours five-membered ring for mat ion Ha (20) e s i / \ (12) four P-hydrogen atoms. These are presumably the two axial hydrogens H,, the equational hydrogens He lying too close to the C, 2p, nodal plane to be resolved [see (19)].…”

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confidence: 99%

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Intramolecular and intermolecular reactions of alkenylsilyl radicals

Chatgilialoglu¹,

Woynar²,

Ingold³

et al. 1983

J. Chem. Soc., Perkin Trans. 2

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The radicals formed during photolysis of di-t-butyl peroxide and a number of alkenyldimethylsilanes have been examined by e.s.r. spectroscopy. Only carbon-centred radicals were observed. These were either secondary alkyl radicals formed by the addition of the initially formed silyl radical to a double bond and/or ally1 radicals formed by hydrogen-atom abstraction from the alkenyl group. In most cases addition to the double bond was an intermolecular process. However, pent-4-enylsilyl radicals undergo intramolecular addition with endo-cyclization to form the six-membered ring being strongly favoured over exocycliration to form the five-membered ring. This preference was confirmed by product studies on 3,3dimethylpent-4-enyldimethylsilane. The factors that control homolytic ex0 : endo cyclization rates for species in which the radical centre is located on a second row element are adumbrated.Free-radical rearrangements are of growing importance since they can provide new approaches to the synthesis of organic compounds and can also be used to determine the absolute rate constants for intermolecular radical-molecule reactions.'S2 The most useful and most carefully studied rearrangement is undoubtedly the ring-closure of the hex-5-enyl radical (1; X = CH2) and related hydrocarbon and heteroatom-containing species including those in which the initial radical centre, X, is on a nitrogen atom or an oxygen a t ~m . ' * ~* ~

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Section: Methodsmentioning

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…At lower temperatures there may be some intermolecular addition. duct (12) was only tentatively identified. If produced, it is formed in only 1% yield.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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