Stobbe reaction

Stobbe reaction org chem A type of aldol condensation reaction represented by the reaction of benzophenone with dimethyl succinate and sodium methoxide to form monoesters of an a-alkylidene (or arylidene) succinic add. shtob-3 re.ak shan ) stoichiometry phys chem The numerical relationship of elements and compounds as reactants and products in chemical reactions., st6i ke am-3 tre )... 

Sterigmatocystin, 48 Stevens rearrangements, 293 Stobbe reaction, 228 Substituent constant, a, 362 constancy of, 368, 372 determination of, 363 physical significance of, 364 and, 362... 

Recently Valla et al. showed that new p-methylenealdehydes synthons could be substituted to 7 ,9 -ionylideneacetaldehydes (derived from a and p-ionones) in a Stobbe reaction [68,69]. 

Miscellaneous Results. The retrogression of- the double bond conjugated with the ester group can be obtained by UV irradiation of acid esters generated in Stobbe reactions. For example, the ,/3-unsaturated... 

A synthesis of ( )-niranthin (11) (31) (Scheme 5) addresses the issue of the two aryl rings having different substituents. jS-Benzylbutyrolactones of type (19) are now readily available in racemic and enantiomeric forms (see next section) yia classical Stobbe reaction procedures. The lithium enolate of (19) (32) reacted... 

Instead of epoxides carbonyl compounds may be used as electrophiles to generate the y-hydroxy carboxylic acid intermediate. In the classical Stobbe reaction (equation 79) succinic esters are deprotonated and treated with aldehydes or ketones to form, via the unstable adduct (211), the paraconic ester (212). 

A more recent and stereocontrolled version of the Stobbe reaction is shown in equation (80). 3-Lac-tone ester (213) is deprotonated to the enolate (214), which adds aldehydes to give either monocyclic... 

Rizzacasa, M. A., Sargent, M. V. The Wittig reaction of 2-(tert-butoxycarbonyi)-1-(methoxycarbonyi)ethyiidenetriphenyiphosphorane a surrogate for the Stobbe reaction. Aust. J. Chem. 1987, 40, 1737-1743. 

Jabbar, S., Gupta, G. Migration of doubie bond in Stobbe reactions. Curr. Set. 1991, 60, 493-494. 

Mezger, F., Simohen, G., Fischer, P. The homoiogous "siiyi-Stobbe-reaction". Synthesis 1991,375-378. 

Stobbe reaction The addition of a 1,4-diester, i.e. a succinate derivative, under basic conditions, to a ketone, followed by an acidic work-up, resulting in an a,(3-unsaturated ester and a (3,y-unsaturated carboxylic acid functionalities. 

Application of the Stobbe reaction to 2-benzoyldibenzofuran gives access to two substituted 1-naphthols 49 and 50 which after cyclisation and possible further manipulation are substrates for pyran formation -with l,l-diphenylprop-2-yn-l-ol (Scheme 17). The resulting heptacyclic photochromes absorb in the range 570 - 600 nm with half-lives of 20 -70 s <98WOP32037>. 

Methyl 10-hydroxybenzo[6]naphtho[2,3-e][l,4]dioxine-8-carboxylate, synthesised from the reaction of 1,2-dihydroxybenzene and 3,4-difluorobenzaldehyde and subsequent Stobbe condensation, is a source of [l,4]benzodioxinonaphtho[l,2-6]pyrans. Similarly, using 2-benzoyl[l,4]benzodioxine in the Stobbe reaction enables indeno analogues to be obtained (Scheme 21) <03USP0168645>. With appropriate gem diaryl substitution in the pyran ring, these molecules show two absorption peaks between 440 - 610 nm and are fast fading. 

Thiophene-2-aldehydes or 2-ketones undergo the Stobbe reaction, and the products 127 are cyclized by Ac20-Na0Ac to the 6-carboxylic esters 128... 

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