3-Hydroxy-l,5-hexadienes

The ninth item in Table 8.7 is called the oxy-Cope rearrangement. It is closely related to the Cope rearrangement of the parent hydrocarbon, 1,5-hexadiene, which, it will be recalled, is capable of an allowed 2n + 2n- - 2a electrocyclic transformation in Chapter 6 (e.g., see Equation 6.61) into itself. The electrocychc process shown here (Scheme 8.84) enjoys an advantage over its parent in that (a) the conversion of the alcohol, 3-hydroxy-l,5-hexadiene, to the aldehyde, 5-hexenal, is readily detectable and (b) the alcohol-to-aldehyde conversion is a synthetically useful process... 

The oxy-Cope is different in that the diene is aldehydic at one end and, indeed, it is the mol of the aldehyde which appears to be the reactive species. It is generally the case that the allylic alcohol (the 3-hydroxy-l, 5-hexadiene on the right in Equation... 

The presence of a hydroxyl group at C-3 position of the 1,5-diene system drives the rearrangement into the less stable enol product, which is converted into stable carbonyl product. This version of this Cope rearrangement is termed the oxy-Cope rearrangement [45]. A particular advantage of this process is that it proceeds under mild conditions, so that many sensitive functional groups are tolerated and is useful for construction of complex organic molecules. The simplest case is the conversion of 3-hydroxy-l,5-hexadiene to 5-hexenal [46]. 

Therefore, a Cope rearrangement can be detected only when the diene is not symmetrical about this bond. Any 1,5-diene gives the rearrangement for example, 3-methyl-l,5-hexadiene heated to 300°C gives 1,5-heptadiene. However, the reaction takes place more easily (lower temperature required) when there is a group on the 3- or 4-carbon with leads to the new double bond being substimted. The reaction is obviously reversible and produces an equilibrium mixture of the two 1,5-dienes, which is richer in the thermodynamically more stable isomer. However, the equilibrium can be shifted to the right for 3-hydroxy-1,5-dienes, because the product tautomerizes to the ketone or aldehyde ... 

The effect of an allylic hydroxy group was first observed in divinylglycol (1,5-hexadiene-c/s-3,4-diol and l,5-hexadiene-frans-3,4-diol). It was shown that the hydroxy substitutions directed the addition of the osmium tetraoxide to syn addition, so that the cfs-diol yielded allitol (all cfs-hexaol) and the trons-diol yielded mannitol. The oxidation of the dienol 35 yielded a lactone ring 36 by cA-dihydroxylation and transesterification... 

In the hydrogenation of l,5-hexadiene-3-ol the double bond in the P position with respect to the hydroxy group reacted more rapidly in all solvents, but the differences were again not pronounced. The effect of solvents on the selectivity of hydrogenation of l,5-hexadiene-3-ol was small. 

Recent advances in the development of well-defined homogeneous metallocene-type catalysts have facilitated mechanistic studies of the processes involved in initiation, propagation, and chain transfer reactions occurring in olefins coordi-native polyaddition. As a result, end-functional polyolefin chains have been made available [103].For instance, Waymouth et al.have reported about the formation of hydroxy-terminated poly(methylene-l,3-cyclopentane) (PMCP-OH) via selective chain transfer to the aluminum atoms of methylaluminoxane (MAO) in the cyclopolymerization of 1,5-hexadiene catalyzed by di(pentameth-ylcyclopentadienyl) zirconium dichloride (Scheme 37). Subsequent equimolar reaction of the hydroxyl extremity with AlEt3 afforded an aluminum alkoxide macroinitiator for the coordinative ROP of sCL and consecutively a novel po-ly(MCP-b-CL) block copolymer [104]. The diblock structure of the copolymer... 

Weitere Beispiele fur diese Art der Mitsunobu-Reaktion sind die Umwandlung eines 2,2-Diaryl-ethanols in 2-Amino-I-(4-benzyloxy-phenyl)-l-(2-benzyloxy-3-methoxy-phenyl)-ethan2 und die Umwandlung von 5-Hydroxy-2-methyl-l-hexen-3-in in 5-Phthalimido-2-methyl-l-hexen-3-in, das (wie oben formuliert) in 5-Amino-4-ethyl-l-hydroxy-2-methyl-2,3-hexadien ubergefuhrt werden kann3 ... 

Ar —S —OH F.n) 5-Hepten-2-ine 4-Hydroxy-l.l.l-trilluoro- E10b2. 217f. (Educt) 1,3-Hexadiene... 

Hexadiene 2-Chloro-l. 1 -difluoro-3-hydroxy-5-methyl-EI0b2, 374 ( —CIF -> En)... 

Chain Transfer to Organometallic Compounds. Hydroxy-terminated poly(methylene-l,3-cyclopentane) has been prepared by selective chain transfer to aluminum in the cyclopolymerization of 1,5-hexadiene with the sterically... 

The compounds that we have identified from sorghum root extracts other than 1 are 5-ethoxysorgoleone (2), 2,5-dimethoxysorgoleone (3), 2-hydroxy-5-methoxy-3-[(8 Z, 11 Z, 14 Z-)-8, 1114 -heptadecatrienyI]-2,5-cyclohexadiene-1, 4-dione (4), 2-hydroxy-5-methoxy-3-[(8 Z,l rZ)-8, ll -pentadecadienyl]-2,5-cyc-lohexadiene-1,4-dione (5), 2-hydroxy-5-methoxy-3-[(8 Z)-8 -pentadecenyl]-2,5-cyclohexadiene-1,4-dione (6), 2-hydroxy-5-methoxy-3-pentadecyl-2,5-cycIo-hexadiene-1,4-dione, also known as dihydromaesanin (7), 4,6-dimethoxy-2-[(8 Z, 11 Z)-8, 1114 -pentadecatrienyl]-1,3-benzenediol (8), 4-methoxy-6-etho-xy-2-[(8 Z,irZ)-8, ir,14 -pentadecatrienyl]-l,3-benzenediol (9) and 6-ethoxy-3-[(10 Z,13 Z)-10, 13, 16 -heptadecatrienyl]-l,2,4-benzenetriol (10) (Fig. 3). 

Dihydroxy-trans-buten-(2)i / -Hydroxy-cis-2-methyl-buten-(2) 4 5-Hydroxy-pemadien-(l, 3)5 1-Hydroxy-cis -buten-(2)6 5-Hydroxy-4-methyl-pentin-(l )7 / -Hydroxymethyl-cyclohepten8 1-Hydroxy-1-hexadien-(2,4)9... 

Alkin-ole werden ebenfalls selektiv zu Alken-olen reduziert (s. a. Bd. V/lc, S. 467). So erhalt man z. B. aus 5-Hydroxy-5-methyl-hexin-(l)-en-(3) an einer Kupfer/Silber-Ka-thode in Athanol/Natriumcarbonat 80-90% d.Th. 5-Hydroxy-5-methyl-hexadien-(l,3)2. Dagegen tritt beim 2,7-Dihydroxy-2,7-dimethyl-octadiin-(3,5) an einer Kupfer-Kathode in Athanol/Natronlauge gleichzeitig Wasser-Abspaltung und Isomerisierung ein und man gewinnt 7-Hydroxy-2,7-dimethyl-octadien-(2,4) (39% d.Th. Kp2 70-720)3 ... 

Fast Green FCF (FD C Green No. 3, Cl Food Green 3) is a triarylmethane dye related to Brilliant Blue, the disodinm 3-[N-ethyl-N-[4-[[4-[N-ethyl-N-(3-snl-fonatobenzyl)amino] -phenyl] (4-hydroxy-2-snlfonatophenyl)methylene] -2,5-cyclo-hexadien-l-ylidene]ammonio-methyl]-benzenesnlfonate. Fast green is a red to brown-violet powder or crystals, solnble in water, sparingly solnble in ethanol, with a maximnm absorption in water at 625 nm. It is not permitted as food colorant in the EU. -"... 

Neuere Beispiele fur die Anwendung der Gabriel-Synthese in ihrer urspriinglichen Form sind u.a. die Herstellung von 4-Chlor-l-phthalimido-2-buten aus l,4-Dichlor-2-buten (65%)1 sowie die erste Stufe der folgenden Synthese von zwei allenischen Amino-alko-holen, 5-Amino-4-ethyl-l-hydroxy-2-methyl-2,3-hexadien (I R =H, R2=R3 = CH3 ... 

FD C Green No. 3 is principally the inner salt disodium salt of ZV-ethyl-/V-[4-[[4-[ethyl[(3-sulfophenyl)methyl]amino]-phenyl](4-hydroxy-2-sulfophenyl)methylene]-2,5-cyclohex-adien- l-ylidene]-3-sulfobenzenemethanaminium hydroxide, with smaller amounts of the isomeric inner salt disodium salt of ZV-ethyl-ZV- [4- [ [4- [ ethyl [ (3-sulfophenyl) methyl ] amino]-phenyl](4-hydroxy-2-sulfophenyl)methylene]-2,5-cyclohex-adien- l-ylidene]-4-sulfobenzenemethanaminium hydroxide of A -eihyl-/V- 4- 4- elhyl (4-sulfophenyl)methyl ]amino]-phenyl](4-hydroxy-2-sulfophenyl)methylene]-2,5-cyclohex-adien-l-ylidene]-4-sulfobenzenemethanaminium hydroxide and of Ar-ethyl-/V-[4-[[4-[ethyl[(2-sulfophenyl)methyl]am-ino]phenyl](4-hydroxy-2-sulfophenyl)methylene]-2,5-cyclo-hexadien-l-ylidene]-3-sulfobenzenemethanaminium hydroxide. 

Diphenylmethylcn- 1-phenyl- 689 2-[Hexadien-(3,5)-yl]-l-[hexadien-(2,4)-yliden]- 557 2-(4-Hydroxy-phenyl)- -benzoyl- 589 2-[Indanyl-(2)-methyl]-1 -athoxycarbonyl- 244... 

Cyasorb UV-9. 2-Hydroxy-4-methoxybenzophenone and Oxybenzone, 79 Cyasorb UV-24, 2,2 -Dihydroxy-4-methoxybenzophenone or Dioxybenzone, 432 Cyasorb UV-531. 2-Hydroxy-4-(octyloxy)benzophenone, 134 Dalbergin. 6-Hydroxy-7-melhoxy-4-phenylcoumarin, 100 Dastib 242. 2-Hydroxy-4-(2-elhylhexyloxy)benzophenone, 135 Dehydrogriseofulvin. 7-Chloro-2, 4,6-trimethoxy-6 -methylspiro[benzofuran-2(3H),l -[2,5]cyclo-hexadiene-3,4 -dione, 458 Diethylene glycol. 2,2 -Oxybisethanol, 134, 507 Diglycol. Diethylene glycol, 507... 

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