Cyclopentenol

Absolute configuration of 2-cyclohexcnol is based on chemical correlation whereas absolute configuration of 2-cyclopentenol and the ee of both alcohols are based on their conversion to the corresponding acetates and H-NMR spectroscopy in the presence of Eu(hcf)3. b Entries 1- 4, 6 10 ratio base/epoxide 3 2 entries 4, 11-21 ratio epoxide/base/additive 1 1.5 1.65. 

The osmylation of l-[Af-methylphenylsulfoximinomethyl]-l-hydroxy-2-cyclopentenols and -2-cyclohexenols, obtained in turn from the corresponding 2-cycloalkenones by the addition of lithiated, V,.S -dimethyl-5-phenylsulfoximine, occurs from the same side as the sulfoximino functionality with complete Ik topicity. Subsequent thermal elimination of the sulfoximine group allows the synthesis of optically pure 2,3-dihydroxycycloalkanones. This method can, therefore, be regarded as proceeding via an auxiliary-controlled osmylation92-93. 

Alkoxy-2-vinylcyclopropanes rearrange stereospecifically to 2-cyclopentenols under very mild conditions. Thus, the lithium salt of 2-vinyl-1-cyclopropanol (204) undergoes the vinylcyclopropane-cyclopentene rearrangement at room temperature (equation 137). ... 

A concerted bond-forming and bond-breaking process is an alternative to Eq. (m). Methyllithium-TMED in CsHi4, or PhLi in THE does not add to PhCHOHCH=CH2 t-BuLi adds exclusively at the terminal carbon to form PhCH=CHCH2Bu-t and PhCHLiCH(Bu-t)CH2Bu-t. Alkene formation is the dominant reaction with 2-cyclopentenol and 2-cyclohexenol ... 

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