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Danishefsky

The regioselectivity of the addition of terminal alkynes to epoxides is improved, when the reagents prepared from the lithiated alkynes and either trifluoroborane or chlorodiethyl-aluminum arc employed (M. Yamaguchi, 1983 S. Danishefsky, 1976). (Ethoxyethynyl)lithium-trifluoroborane (1 1) is a convenient reagent for converting epoxides to y-lactones (M. Naka-tsuka, 1990 see p. 327f. cf. S. Danishefsky, 1976). [Pg.64]

Some straightforward, efficient cyclopentanellation procedures were developed recently. Addition of a malonic ester anion to a cyclopropane-1,1-dicarboxylic ester followed by a Dieckmann condensation (S. Danishefsky, 1974) or addition of iJ-ketoester anions to a (l-phenylthiocyclopropyl)phosphonium cation followed by intramolecular Wittig reaction (J.P, Marino. 1975) produced cyclopentanones. Another procedure starts with a (2 + 21-cycloaddition of dichloroketene to alkenes followed by regioselective ring expansion with diazomethane. The resulting 2,2-dichlorocyclopentanones can be converted to a large variety of cyclopentane derivatives (A.E. Greene. 1979 J.-P. Deprds, 1980). [Pg.83]

A major difficulty with the Diels-Alder reaction is its sensitivity to sterical hindrance. Tri- and tetrasubstituted olefins or dienes with bulky substituents at the terminal carbons react only very slowly. Therefore bicyclic compounds with polar reactions are more suitable for such target molecules, e.g. steroids. There exist, however, several exceptions, e. g. a reaction of a tetrasubstituted alkene with a 1,1-disubstituted diene to produce a cyclohexene intermediate containing three contiguous quaternary carbon atoms (S. Danishefsky, 1979). This reaction was assisted by large polarity differences between the electron rich diene and the electron deficient ene component. [Pg.86]

A highly successful route to stereoisomers of substituted 3-cyclohexene-l-carboxylates runs via Ireland-Claisen rearrangements of silyl enolates of oj-vinyl lactones. The rearrangement proceeds stereospeaifically through the only possible boat-like transition state, in which the connecting carbon atoms come close enough (S. Danishefsky, 1980 see also section 4.8.3, M. Nakatsuka, 1990). [Pg.87]

S. E. Danishefsky and S. Danishefsky, Progress in Total Synthesis (Appleton-Century-Crofts, New York, 1971). [Pg.99]

Bicyclic Core of the Esperamiein/Caliehemicin Class of Antitumor Agents Schreiber, Danishefsky, Magnus,... [Pg.366]


See other pages where Danishefsky is mentioned: [Pg.153]    [Pg.209]    [Pg.365]    [Pg.365]    [Pg.365]    [Pg.366]    [Pg.366]    [Pg.269]    [Pg.269]    [Pg.422]    [Pg.20]    [Pg.214]    [Pg.175]    [Pg.65]    [Pg.442]    [Pg.452]    [Pg.92]    [Pg.176]    [Pg.176]    [Pg.285]    [Pg.285]    [Pg.158]    [Pg.86]    [Pg.56]    [Pg.80]    [Pg.82]    [Pg.87]    [Pg.91]    [Pg.99]    [Pg.102]    [Pg.128]    [Pg.133]    [Pg.234]    [Pg.73]    [Pg.331]    [Pg.441]    [Pg.441]    [Pg.798]    [Pg.365]    [Pg.371]    [Pg.372]    [Pg.373]    [Pg.378]   
See also in sourсe #XX -- [ Pg.71 , Pg.289 , Pg.514 ]

See also in sourсe #XX -- [ Pg.394 ]

See also in sourсe #XX -- [ Pg.563 ]

See also in sourсe #XX -- [ Pg.271 ]

See also in sourсe #XX -- [ Pg.918 , Pg.923 ]

See also in sourсe #XX -- [ Pg.164 ]




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DANISHEFSKY Silyloxydienes

Danishefski 4 + 2] cycloaddition

Danishefski’s diene

Danishefsky condensation

Danishefsky diene

Danishefsky dimethyl-substituted

Danishefsky indole synthesis

Danishefsky s diene cycloaddition

Danishefsky s diene cycloadditions

Danishefsky s dienes

Danishefsky substituted

Danishefsky synthesis

Danishefsky synthesis of avermectin

Danishefsky synthesis of mitomycins

Danishefsky triene

Danishefsky trimethylsilyloxy)dienes

Danishefsky, Samuel

Danishefsky-Brassard diene

Danishefsky-Hungate synthesis

Danishefsky-type dienes

Danishefskys Synthetic Approach to Dynemicin

Danishefskys Total Synthesis of Dynemicin

Danishefskys Total Synthesis of the CP-Molecules

Danishefsky’s diene

Danishefsky’s diene cycloaddition reactions

Danishefsky’s total synthesis

Diels-Alder reactions with Danishefsky diene

Diene Danishefsky-type

Dienes Danishefsky

Dienes Danishefsky diene

Dienes Danishefsky’s diene

Hetero Danishefsky diene

Hetero-Diels—Alder reactions of Danishefsky’s diene

Methyl crotonate reaction with Danishefsky’s diene

Of Danishefsky’s diene

Park and Danishefsky

The Danishefsky Synthesis

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