Alkenes reagents for

Peroxy acids have been seen before as reagents for the epoxidation of alkenes (Section 6 18)... 

Since borane BH3 reacts with only one or two equivalents of a sterically hindered alkene, it is possible to prepare less reactive and more selective borane reagents R2BH and RBH2 respectively. In addition to disiamylborane 8 and thexylbo-rane 10, the 9-borabicyclo[3.3.1]nonane (9-BBN) 14 is an important reagent for hydroboration, since it is stable to air it is prepared by addition of borane 2 to cycloocta-1,5-diene 13 ... 

The addition usually takes place from the sterically less hindered side of the alkene. The stereochemical course of the addition can be controlled by suitably positioned oxygen center that can coordinate to the organozinc reagent. For example the reaction with 4-hydroxycyclopentene 6 as substrate exclusively yields the c -3-hydroxybicyclo [3.1.0] hexane 7 ... 

Allylboron compounds have proven to be an exceedingly useful class of allylmetal reagents for the stereoselective synthesis of homoallylic alcohols via reactions with carbonyl compounds, especially aldehydes1. The reactions of allylboron compounds and aldehydes proceed by way of cyclic transition states with predictable transmission of olefinic stereochemistry to anti (from L-alkene precursors) or syn (from Z-alkene precursors) relationships about the newly formed carbon-carbon bond. This stereochemical feature, classified as simple diastereoselection, is general for Type I allylorganometallicslb. 

The equilibrium (1) at the electrode surface will lie to the right, i.e. the reduction of O will occur if the electrode potential is set at a value more cathodic than E. Conversely, the oxidation of R would require the potential to be more anodic than F/ . Since the potential range in certain solvents can extend from — 3-0 V to + 3-5 V, the driving force for an oxidation or a reduction is of the order of 3 eV or 260 kJ moR and experience shows that this is sufficient for the oxidation and reduction of most organic compounds, including many which are resistant to chemical redox reagents. For example, the electrochemical oxidation of alkanes and alkenes to carbonium ions is possible in several systems... 

Many other reagents for converting alkenes to epoxides,including H2O2 and Oxone , VO(0-isopropyl)3 in liquid C02, ° polymer-supported cobalt (II) acetate and 02, ° and dimethyl dioxirane.This reagent is rather versatile, and converts methylene oxiranes to spiro-epoxides. ° ° One problem with dimethyloxirane is C—H insertion reactions rather than epoxidation. Magnesium monoperoxyphthalate is commercially available, and has been shown to be a good substitute for m-chloroperoxybenzoic acid in a number of reactions. 

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