Boranes, applications, synthetic review

The chemistry of unsaturated organoboranes often differs markedly from that of their saturated analogues. Both vinylic and allylic boranes react readily with many substrates toward which trialkylboranes are inert90 . Allylic boranes can be synthesized selectively via direct hydroboration of an appropriate allene or conjugated diene and are of immense synthetic importance 91 93). Mikhailov in his book and review 7,94) has documented the synthetic applicability of allylic boranes with caution of high thermal reactivity with respect to allylic rearrangement. For example, (l-methyl-2-propenyl)dialkylboranes rearrange spontaneously to the 2-butenyl isomer even at -78 °C (Eq. 40). 

A soln. of borane in tetrahydrofuran added dropwise at 0° to cyclohexene and dry tetrahydrofuran, warmed 3 hrs. at 50°, cooled to -78°, stirred and treated with oxygen until Og-absorption ceases after 2 moles have been consumed, then aq. 30%-HgOg added dropwise, and stirred 0.5 hr. at 0° cyclohexyl hydroperoxide. Y 80-95%. - The low-temp, autoxidation of organoboranes provides a rapid and convenient synthesis of alkyl hydroperoxides. F. e. s. H. C. Brown and M. M. Midland, Am. Soc. 93, 4078 (1971) synthetic applications of organoboranes, review, s. Chem. Britain 7, 458 (1971) radical reactions with boranes, review, s. Ang. Ch. 84, 702 (1972). 

Borane/hydrogen peroxide Synthetic applications of organoboranes Review... 

A brief review has recounted the discovery and applications of phosphametallocenes. The synthesis and structure of l,l -diphospha[2]ferrocenophane have also appeared these derivatives are obtained starting with 1-phenyl-3,4-dimethylphosphole-2-carboxaldehyde in a six-step synthetic procedure. A general mini-review on phosphorus heterocycles also highlights the synthesis and use of a number of phosphaferrocenes. A phospha-ferrocenium compound has also been prepared as its triiodide [Gp Fe(Ci2H2oP)][l3]- Borane adducts of phosphaferrocenes have also been obtained simply by treating the appropriate phosphaferrocenes with boron tribromide. 

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