2-Vinyl-3-alkenols

Vinyl-3-alkenols. rj -Pet from pentadienyl acetates with lO and methyl benzoate. The compli mild base to give the dienols. 

Vinyl-3-alkenols. yj -Pentadienylchromium complexes can be generated from pentadienyl acetates with (OC)iCr(PhCOOMe), which is obtained from CrCCO) and methyl benzoate. The complexes condense with aldehydes in the presence of a mild base to give the dienols. 

Terminal vinylic fluorine bonds in substituted allylic alkenols are reduced selectively with lithium aluminum hydride in high yields. The reduction of l,l,2-trifluoroalk-l-en-3-ols in refluxing diethyl ether affords l,2-difluoroalk-l-en-3-olsas a mixture of ( )- and (Z)-isomers in 76-82% yield together with a small amount of l,l,2-trifluoroalk-2-enes (E- and Z-isomers).82 Similarly, lithium 3,3-difluoroalk-2-ene oxides 1 afford unstable l-fluoroalk-l-en-3-ols 2 (EjZ 95 5) in 80-90% crude yields.88 84... 

The levels of 1,5-asymmetric induction in the palladium-catalyzed alkoxy-carbonylations of alkenols to form 2,6-disubstituted tetrahydropyrans have been shown to be quite reasonable (Table 10 and equation 50).144 Recent studies have shown that cyclization with palladium(II) acetate in DMSO in the absence of CO results in controlled -hydride elimination to form vinyl-substituted tetrahydropyrans with high levels of 1,4- and 1,5-asymmetric induction (equation 51).144b... 

After conversion to unsaturated sulfonates through reaction with vinyl or allyl sulfonyl chlorides, both primary and secondary alkenols afford dihydro-1,2-oxathiane 2,2-dioxides through a Ru-catalysed RCM (Scheme 55) <06T9017>. 

Vinyl and allyl sulfonates derived from primary and seeondary alkenols and from propargylie alcohols undergo an RCM in the presence of Ru catalysts to give dihydro 1,2-oxathiane 2,2-dioxides <03SL667>. 

Similar reactions using dihydropyrans and dihydrofurans furnish cyclobutanes or alkenol products upon hydrolysis (Scheme 18). As with the previous applications, zirconacyclic intermediates are implicated. Differences in stereochemistry in the observed products versus the open chain vinyl substrates are thought to arise from geometric restrictions imposed by the bicyclic intermediates. 

A chiral Ir(I) catalyst derived from the amino-(2,2 -biphenoxy)phosphine 37 promotes the synthesis of optically active 3-amino-l-alkenes from 2-alkenols, which are activated by (Eto)5Nb/ l-Vinyl-l,2,3,4-tetrahydroisoquinolines are obtained in good yields in the Pd-catalyzed process. Enantioselectivity is induced by the atropisomeric 38. ... 

Enols, alkenols - The term refers specifically to vinylic alcohols, which have the structure HOCR =CR2. Enols are tautomeric with aldehydes (R = H) or ketones (R not equal to H). [5]... 

The Pd(PhCN)2Cl2-catalyzed cross-coupling reaction of 1-alkenylboronic reagents with 3,4-epoxy- 1-butene afforded a mix-toe of 2-(l-vinyl)-3-alkenols and alka-2,5-dienols (eq 21). ... 

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