Tiglic acid, addition

However, in the case of a-substituted unsaturated esters (4), as for example methacrylic or tiglic acid esters, diazomethane addition results in the formation of stable A pyrazolines (5). The latter products require halogen acids for conversion to the isomeric nonconjugated A -pyrazolines (6). 

Only 5% of the cis isomer, tiglic acid, was produced. In addition, certain carbanions in which the negative charge is stabilized by d-orbital overlap can maintain configuration (p. 233) and SeI reactions involving them proceed with retention of configuration. 

Azetidinones are also formed on photolysis of cis-a-phenyl-cinnamanilide (361), but in addition a small quantity of a cis-trans mixture of 3,4-diphenyl-3,4-dihydroquinolin-2-one (362) was obtained. The yield of quinolinone was considerably increased in the photocyclization of alkyl-substituted acrylanilides.389 The anilide (363) of tiglic acid, for example, was converted into the anilide (364) of angelic acid by photochemical cis-trans isomerism, and into a mixture of cis- and [Pg.103]

The TV-methoxy-jV-methylamide of tiglic acid (17) is used as an aeylating agent in a procedure developed by Weinreb.9 Lithiated aromatic species 18 attacks Weinreb amide 17 with formation of the chelate 19. which is hydrolyzed to ketone 5. Use of Weinreb amide 17 circumvents the primary threat here multiple addition and formation of a tertiary alcohol. Since complex 19 decomposes only in the course of workup, the ketone 5 itself is protected against further nucleophilic attack.10 "BuLi, LiCl. THF. 0 C->RT 17. 77%. 

HMPT exerts a similar effect in the reactions of the dianion of tiglic acid with aldehydes, but addition of HMPT to reactions of the lithium salt of crotonaldehyde cyclohexylimine with aldehydes results in a complex mixture of products. 

An absolute asymmetric synthesis has been also successfully performed via the heterogeneous addition of OSO4 on the double bond of achiral tiglic acid that crystallizes in a centrosymmetric crystal where one of the enan-tiotopic faces is blocked during the reaction [62],... 

C4C im][PF6] large variety Ru(OAc)2(fo/-BINAP) Tiglic acid Atropic acid 5-100 bar, 20 °C IPrOH as co-solvent, H20 as co-sol- [12] vent product extracted with scC02 catalyst solution can [13] be reused at least four times studies of different 112-pressure, co-solvents and additives on enantioselectivity studies on the ee by changing ionic liquid, strong effect of the anion effect of C02-expanded ionic liquids. 

Nucleophilic addition of thiophenol to chiral tiglic acid-derived imides proceeds in excellent yields and diastereoselectivities (eq 59). Complete turnover of both the a- and p-centers results from the use of the (Z) rather than (E) isomer. Poor p-induction was found with the imides derived from cinnamic acid. 

Simple a-substituted styrenes are reduced in the presence of RuCl2(DuPhos)(DMF) . The reactivity of the ruthenium catalyst is enhanced by the addition of potassium te/t-butoxide, which may facilitate generation of a ruthenium hydride. The products are obtained under low hydrogen pressures and selectivities obtained are up to 89% ee (eq 8). Neutral Rh-DuPhos complexes catalyze the hydrogenation of a,3-unsaturated acids such as tiglic acid (eq 9). The product is obtained in quantitative yield and good enantioselectivity. ... 

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