Styrene oxide reduction

Figure 5.7 Environmental factors E for the biocatalytic (a) and chemical catalytic (b) synthesis of (S)-styrene oxide (Scheme 5.3) using the software EATOS. The reduction of the environmental factor achieved by solvent recycling is indicated.

The complex [Rh(COD)L L2]+, where L1 = PPh3 and L2 = pyridine, and a neutral benzoate complex, Rh(COD)(PPh3)(OCOPh), also effect highly selective hydrogenation of 1-alkynes to 1-alkenes as well as reduction of 1-alkenes and ketones to alcohols (139) the one equivalent of base required may be related to monohydride formation [Eq. (25)]. The bisphosphine complexes also catalyze reduction of styrene oxide to 2-phenylethanol and phenylacetaldehyde (140) ... 

This enantioselective reduction can be used for synthesis of chiral 1-substituted oxiranes.1 2 3 Thus reduction of 2-chloroacetophenone with B2H6 catalyzed by 1 (1 mole %) results in (S)-( + )-(chloromethyl)benzenemethanol, which in the presence of base converts to (S)-( - )-phenyloxirane (styrene oxide). 

A recent paper by Kwiatek and co-workers1891 discloses the use of a homogeneous catalysis system for the hydrogenation of epoxides. Reduction of cyclohexene oxide to cydohexanol, and of styrene oxide to 2-phenylethanol, was carried at atmospherio pressure, using Ks[Co(CN) ] to catalyze the reaction. 

Preliminary experiments were performed to study the (electroactive) behaviour of styrene containing TRAP at a platinum ultramicro disc electrode, which was obtained as described in Chapter 1, pages 21-24. However, in the range where copper activity is observed (see later) no additional reactions of the solvent or the electrolyte were observed. Outside this potential window, oxidation of styrene and reduction of the electrolyte were observed. As these potential ranges are not interesting for the purpose of detection of Cu(II) and Cu(I), they are not further described in this chapter. 

Scheme4.62. Reductive ring opening of styrene oxides [250, 260-262],...

Fuchs, R. van der Werf, C. A. Direction of ring opening in the reduction of p-substituted styrene oxides with LiBH4. J. Am. Chem. Soc. 1954, 76, 1631-1634. 

Another method to monitor DNA damage in films employed a cationic electroactive probe that binds better to ds-DNA than to damaged DNA. Co(bpy)3+ was used to probe films of (PDDA/ds-DNA)2 grown layer-by-layer on PG electrodes first coated with a layer of PSS.[46] After incubation of (PDDA/ds-DNA)2 films with styrene oxide, electrodes were rinsed, placed into 20 pM Co(bpy)i+, and the Com/Con reduction peak at 0.04 V vs. SCE from the DNA-bound complex was monitored by SWV. Peak current decreased with increasing time of reaction with... 

Newman, Underwood, and Renoll (48) studied the reduction of 1,2-epoxydecane. Over Raney nickel the product was 1-decanol. In the presence of alkali, however, the main product was 2-decanol. Chemical reduction also leads to 2-decanol. It is interesting to note that, when styrene oxide is reduced over Raney nickel, the primary alcohol is received as the main product whether or not alkali is present. 

The Langmuir-Hinshelwood kinetic model describes a reaction in which the rate-limiting step is reaction between two adsorbed species such as chemisorbed CO and 0 reacting to form C02 over a Pt catalyst. The Mars-van Krevelen model describes a mechanism in which the catalytic metal oxide is reduced by one of the reactants and rapidly reoxidizd by another reactant. The dehydrogenation of ethyl benzene to styrene over Fe203 is another example of this model. Ethyl benzene reduces the Fe+3 to Fe+2 whereas the steam present reoxidizes it, completing the oxidation-reduction (redox) cycle. This mechanism is prevalent for many reducible base metal oxide catalysts. There are also mechanisms where the chemisorbed species reacts... 

Two types of asymmetric reactions were conducted synthesis of styrene oxide and reduction of olefinic ketones. 

The first successfiil attempt to simulate some aspects of alkaline phosphatase activity by using a pendemt donor macrocycle was done using the Zn(II) complex of hgand (3), which was formed from 2,6-dioxocyclen (cyclen= 1,4,7,10-tetraazacyclododecane) (1) (17) by reaction with (S)-styrene oxide followed by reduction of the intermediate diamide (2) (IS). 

This reduction is useful for synthesis of optically active styrene oxide (equation I). 

Pai et al. (1983) measured hole mobilities of a series of bis(diethylamino)-substituted triphenylmethane derivatives doped into a PC and poly(styrene) (PS). The mobilities varied by four orders of magnitude, while the field dependencies varied from linear to quadratic. In all materials, the field dependencies decreased with increasing temperature. The temperature dependencies were described by an Arrhenius relationship with activation energies that decrease with increasing field. Pai et al. described the transport process as a field-driven chain of oxidation-reduction reactions in which the rate of electron transfer is controlled by the molecular substituents of the hopping sites. 

Alkene oxides may also be cleaved by reduction with lithium aluminum hydride as in the preparation of a-phenylethyl alcohol from styrene oxide (9 4%). ... 

Phenylpropene oxide is selectively reduced in the presence of rra 5-stilbene oxide even with an excess amount of sodium borohydride (equation 16), and a similar system using lithium borohydride (LiBHa) also shows selective reduction of a styrene oxide in the presence of a benzamide. ... 

The effect of additives and of modified aluminum and borohydrides has been extensively examined in efforts to enhance reactivity and improve selectivity. The system of LAH and aluminum chloride was early applied to achieving opposite regioselectivity. For example, the reduction of styrene oxide with this system takes place at the benzylic position to give 3-phenethyl alcohol as the major product, and the same effect is observed with 1,4-dialkylcyclohexene oxide (equation 17). 4... 

Although diborane (BH3)2 reduces epoxides, it usually gives a mixture of products in addition to the usual alcohols. The reduction of styrene oxide derivatives with diborane has been studied in order to develop a new route to 1,3-diols from epoxides (equation 19).4 a,3-Unsaturated epoxides undergo... 

Reduction of epoxides-1 Styrene oxide and similar aryl epoxides undergo rapid anti-Markownikov opening when reduced with diborane in the presence of boron... 

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