Allylic alcohols olefin regioselectivity

Blechert carried out a tandem reaction of enynes in the presence of olefins instead of ethylene (Scheme 21). Treatment of cyclopentenol derivative 58a with Ic in the presence of an alkene affords 59a. The five-membered ring in estrone 58b is cleaved by Ic to give 59 and an alkene part is introduced on the six-membered C ring. However, cycloalkenyl amine derivative 60 is treated in a similar manner in the presence of an allyl alcohol derivative to give pyrrolidine derivative 61, and in this case, an alkene part is introduced on the diene moiety. Presumably, ruthenium carbene complex XVI reacts with an alkyne part to produce the pyrrolidine ring with a regioselectivity opposite to the other cases. 

Oxovanadium(V) and oxomolybdenum(VI) were incorporated into crosslinked polystyrene resins functionalized with iminodiacetic acid or diethylenetriamine derivatives 921 The polymer complexes were used as catalysts in the oxidation of olefins with f-butylhydroperoxide. Vanadium(V) complexes promote the epoxidation of allylic alcohols in a highly regioselective manner, e.g., 2,3-epoxide was obtained in 98 % selectivity from e-geraniol at 80 °C. The catalytic activity of the vanadium(V) complexes is generally higher than that of the molybdenium(VI) complexes in the oxidation of allylic alcohols, whereas an opposed trend holds for the epoxidation of cyclohexene. 

A. Krief, A.-M. Laval, Ortho-Nitrophenyl Selenocyanate, a Valuable Reagent in Organic Synthesis Application to One of the Most Powerful Routes to Terminal Olefins from Primary-Alcohols (The Grieco-Sharpless Olefination Reaction) and to the Regioselective Isomerization of Allyl Alcohols), ... 

A. Krief and A.-M. Laval, u-Nitrophenyl selenocyanate, a valuable reagent in organic synthesis Application to one of the most powerful routes to terminal olefins from primary-alcohols (the Grieco-Sharpless olefination reaction) and to the regioselective isomerization of allyl alcohols, Bull. Soc. Chim. Fr. 1997,13, 869-874. 

Syntheses of Alkylidene cyclobutanes Via the Selenoxide Route The selenoxide route which was particularly inefficient with cyclopropyl derivatives in this case proved suitable. The reaction is completely regioselective in the case of P-hydroxy selenides, which produce exclusively the allyl alcohols possessing the endo-cyclic double bond (Scheme 39)s7), whereas a mixture of endo and exo olefins is... 

Electrochemical oxidations have been previously mentioned.122 A novel application is the regioselective epoxidation (80% conversion 90% selectivity) at the 6,7-bond of geranyl and neryl esters and phenyl sulphones.214 Another is the one-step conversion of olefins into allylic alcohols via electrooxidative-oxyselenylation-deselenylation, e.g. (97)—>(99). This method has been applied to the synthesis of (100) which can be converted (70%) into marmelolactone [(101) from quince], and... 

Thermolysis of 24 at 180-190°C for 6 days gave a 35% yield of the desired endo product 35a contaminated with the exo isomer 35b. The ratio of these adducts was quite acceptable (4 1 endo exo. With the basic cytochalasin ring system in hand, what remained was the introduction of the required unsaturation adjacent to the lactone and oxidation of the cyclohexene ring. The former was achieved in 70-76% yield by selenylation followed by oxidative elimination to afford solely the ( )-olefin 36. Hydroxylation was initiated by nitrogen acylation followed by stereo- and regioselective epoxidation of the A olefin. Deacylation and desilylation then afforded cytochalasin F (37) in 51% yield. Cytochalasin B (20) was obtained in a similar way by isomerization of the intermediate epoxide to the allylic alcohol with aluminum isopropoxide, followed by deacylation and desilylation. 

The first example of olefin hydrocohaltation and its subsequent oxygenation was reported by Okamoto [39]. Later, Pattenden studied the hydrocohaltation of 1,3-dienes and found that they led exclusively to 1,4-addition. Under aerobic condition, tertiary peroxycobaloximes are produced. After reductive treatment, tertiary allylic alcohols are obtained (Scheme 14, Eq. 14.1). Interestingly, reactions with TEMPO afford primary alkoxyamines and after reductive treatment primary allylic alcohols (Scheme 14, Eq. 14.2). This change in regioselectivity may be attributed to steric effects [40]. 

The Wacker reaction has been applied to numerous simple olefins such as a-olefins and cycloalkenes, or to functionalized olefins such nitroethylene, acrylonitrile, styrene, allyl alcohol, or maleic acid [3]. The carbonyl group is formed at the carbon atom of the double bond where the nucleophile would add in a Markovnikov addition. Reversal of the regioselectivity has only been observed with particular substrates such as 1,5-dienes [9]. Conversion and selectivity for the oxidation of these olefins were found to be very dependent on the water solubility of the olefin. Indeed, high molecular weight olefins do not react under the standard... 

---