Heterodienophiles—V

Krow, Grant R.; Pyun, C.; Rodebaugh, Ronald K.; Marakowski, J.

doi:10.1016/s0040-4020(01)97542-8

Cited by 27 publications

(14 citation statements)

References 19 publications

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“…Baeyer-Villiger oxidation [27] of (+)-14 (3-C1C,H4CO,H, NaHCO,, CH,Cl,) afforded (-)-15 (92 YO) with high regioselectivity, as expected [28]. Deprotonation of uronolactone (-)-15 with (Me,Si),NLi (LiHMDS; 1.0 equiv.)…”

Section: Cyano-l5-dimethyl-7-oxabicyclo[221]hept-5-en-2-endo-yl (1mentioning

confidence: 78%

“…phase was extracted with CH,CI, (40 ml, twice), the combined org. extract washed with brine (20 ml) (7), 305 (27), 287 (26), 247 (25), 229 (73, 203 (58), 189 (22) 2980,2940,2920,2840,1460,1360,1250,1210,1100,1070,1050,1010,955,900,865,850,760,660 ((i)-30). A mixture of(+)-29 (750 mg, 2.07 mmol), Ac,O (10 ml), and pyridine (1 ml) was stirred at 20" for 1 h. After addition oftoluene (50 ml), the solvent was evaporated, the residue taken with toluene (10 ml), and the solvent evaporated (twice).…”

Section: ~~-Altro-heptono-l4-lactone ((+)-27)mentioning

confidence: 99%

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Synthesis of Polypropionate Fragments Containing Tertiary‐Alcohol Moieties. Cross‐aldolisations with lithium enolates of 7‐oxabicyclo[2.2.1]heptan‐2‐one derivatives

Kernen

Vogel

1995

Helvetica Chimica Acta

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The Diels-Alder adduct of 2,4-dimethylfuran to I-cyanovinyl (1'R)-camphanate ( ( + ) cyano-l,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl (1'S)-camphanate ((-)-3)).All these cross-aldolisations are highly em-face selective for the bicyclic ketones. The best stereochemical matching is obtained when the lithium enolates and (x -methyI-substituted aldehydes can realize a 'chelated transition state' that obeys the Cmrn and Fefkin-Anh models (steric effects). Polypropionate fragments containing eleven contiguous stereogenic centres and tertiary-alcohol moieties are thus prepared with high stereoselectivity in a convergent fashion. The chiral auxiliaries ((1R)-and (1s)-camphanic acid) are recovered at the beginning of the syntheses.A large variety of natural products of biological interest contain polypropionate fragments (chain with alternating OH and Me substituents) and analogues involving tertiary-alcoholic centres [2]. Several methods and strategies have been developed to provide access to these systems which possess a high density of stereochemical information [3]. The control of the stereochemistry can rely on pericyclic reactions such as the Claisen rearrangement [4]

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Section: Cyano-l5-dimethyl-7-oxabicyclo[221]hept-5-en-2-endo-yl (1mentioning

confidence: 78%

Section: ~~-Altro-heptono-l4-lactone ((+)-27)mentioning

confidence: 99%

Synthesis of Polypropionate Fragments Containing Tertiary‐Alcohol Moieties. Cross‐aldolisations with lithium enolates of 7‐oxabicyclo[2.2.1]heptan‐2‐one derivatives

Kernen

Vogel

1995

Helvetica Chimica Acta

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“…Thus, photoreactions carried out under neutral conditions at room temperature may be useful for nitrogen insertion into bicycloC2.2. llheptanones, which process has been extensively reviewed by Krow,26 to give lactams such as 12,18 and 19.…”

Section: Discussionmentioning

confidence: 99%

Photoinduced molecular transformations. Part 119. Photochemical nitrogen insertion into bicyclo[2.2.1]heptanones; the photochemistry of oximes of (+)-fenchone and (+)-camphor

Suginome¹,

Furukawa²,

Orito³

1991

J. Chem. Soc., Perkin Trans. 1

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“…C33H580S2 requires C, 74.1; H, 10.9%); and 3a-butyl-3p-hydroxy-14amethyl-4-nor-5a-cholest-8-ene (6) (141 mg, 9.5%) as a thick colourless oil which could not be induced to crystallize; v,,, 3 605, 1 338, 1 285, 1 160, 1 140, 1040, 994, and 968 cm-'; 6 2. 16 (2 H, m), 1.08, 0.73, 0.90, and 0.83; m/z 442 (M'), 427, 409, 369, and 43 (Found: C, 84.3; H, 12.4. C31H540 requires C, 84.1; H, 12.3%).…”

Section: Set Tiementioning

confidence: 99%