L,2-Bis- hydroxymethyl

Chiral Alcohols and Lactones. HLAD has been widely used for stereoselective oxidations of a variety of prochiral diols to lactones on a preparative scale. In most cases pro-(3) hydroxyl is oxidized irrespective of the substituents. The method is applicable among others to ftf-l,2-bis(hydroxymethyl) derivatives of cyclopropane, cyclobutane, cyclohexane, and cyclohexene. Resulting y-lactones are isolated in 68—90% yields and of 100% ee (164,165). 

The carbonylation of (2-ethynylphenyl)methanol is catalyzed by Pd(OAc)2 in the presence of 2-(diphenylphos-phino)pyridine (2-PyPPh2) to provide 4-methyleneisochroman-3-one, isolated in poor yield due to its instability (Equation 456) <2002TL753>. The synthesis of isochroman-3-one can be achieved by a palladium and Hi-mediated carbonylation of l,2-bis(hydroxymethyl)benzene <1998BCJ723>. 

The absolute configuration and optical purity of the lactone was established by its hydrolysis and epimerization to (1R, 2R)-trans-2-hydroxymethylcyclohexanecarboxylic acid followed by lithium aluminum hydride reduction to (1R, 2R)-trans-l,2-bis(hydroxymethyl)cyclohexane.4 By XH NMR,5 the e.e. was > 97%. 

The asymmetric transesterification of cyclic me o-diols, usually with vinyl acetate as an irreversible acyl transfer agent, includes monocyclic cycloalkene diol derivatives, bicyclic diols, such as the ej o-acetonide in eq 12, bicyclic diols of the norbomyl type, andorganometallic l,2-bis(hydroxymethyl)ferrocenepossessing planar chirality. 

The reaction of Si(OH)2Pc with l,2-bis(hydroxymethyl)carborane at 500-670K or in H2SO4 was examined But only pyridine soluble oligomers were isolated. 

Two methods have been reported for the preparation of closo-1,2-dicarbadodecaborane(12) (or(/io-carborane). The first procedure involves the direct reaction of acetylene with a (Lewis base)2BioHi2 compound. The second procedure involves the oxidative degradation of l,2-bis(hydroxymethyl)-cZoso-l,2-dicarb-adodecaborane(12). ... 

Examples for preparing optically active gera-difluorocyclopropanes. (a) Itoh, T., Mitsukura, K. and Furutani, M. (1998) Efficient synthesis of enantiopure l,2-bis(hydroxymethyl)-3,3-difluorocyclopropane derivatives through lipase-catalyzed reaction. Chem. Lett., 903-904. 

We next became interested in the possibility of extending this to a seven-membered cyclic ketal. It was immediately recognized that if the yield of the cyclic compound were not nearly quantitative, the resulting polymer would be cross-linked. In our previous work (16) the cis- and trans-l,2-bis (hydroxymethyl)-cyclohexane were prepared. When either the cis- or trans-diol was condensed with 1,4-cyclohexanedione, a 92% yield of the corresponding model compound was obtained. 

Methoxyphthalan is obtained by partial oxidation of l,2-bis(hydroxymethyl)-benzene with hypochlorite in methanol treatment with lithium diisopropylamide... 

The use of formaldehyde as the carbonyl reagent fails to produce the expected l,2-bis(hydroxymethyl)carborane from dilithiocarborane 334). It has since been found, however, that formaldehyde readily reacts with this hydroxymethylcarborane to form a cyclic formal (XLVIII) 351). 

In what appears to be an oxidation followed by a decarboxylation step, the action of aqueous alkaline permanganate on l,2-bis(hydroxymethyl)car-borane (or its diester) provides a convenient route to the parent carborane (327). 

A cyclic ether, l,2-(2 -oxapropylene)carborane (L), is formed by the action of hot, concentrated sulfuric acid on l,2-bis(hydroxymethyl)car-borane 327, 334). 

Thus, benzylation of rraRS-3,3-diethoxy-l,2-bis(hydroxymethyl)cyclobutane (24)23aJ> to 25 (Scheme 3) was followed by hydrolysis to tra s-2,3-bis(benzyloxymethyl)-cyclobutanone (26).28 Reduction of 26 with LS-Selectride to ( )-(lo,2a,3p)-2,3-bis(benzyloxymethyl)cyclobutanol (27) occurred with no indication (by and NMR) of the diastereomeric alcohol 29 having been formed. Acetylation of 27 gave 28, which, when subjected to treatment with Pseudomonas cepacia lipase, yielded (+)-28 (>99% ee and (-)-27 (>99% ee ). The structural assignments for (+)-28 and (-)-27 were accomplished by conversion into the enantiomeric alcohols 30 and 31 and comparing the optical rotation data for each product with the reported values for these latter conqx>unds. 

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