Baker’s Yeast Mediated Biohydrogenation of 2-Substituted Allyl Alcohols: Synthesis of Enantiomerically Pure (2S)-3-Benzyloxy-2-methyl-1-propanol

Modular Synthesis of Dihydroxyacetone Monoalkyl Ethers and Isosteric 1‐Hydroxy‐2‐alkanones

“…Dihydroxyacetone monoethers 3 , mostly the benzyl derivative, have been described for studies of stereoselective biochemical reductions,4–7 but derivatives containing aromatic or larger organic groups have also been prepared for use as pharmaceutical building blocks and in cosmetic applications 8,9. Starting materials for the known synthetic routes (Figure 2) were either the acetal‐protected dihydroxyacetone monomer 5 4,10 or the dimer 6 (each three steps overall from 1 ),8,11 whereas others started from epichlorohydrin 7 (five steps)6 or acrolein acetal via 8 (four steps) 7,12…”

Catalysts for Fine Chemical Synthesis

“…One facet of the whole cell work that draws attention is the sometimes profitable operation of a cascade of reactions in the multi-enzyme portfolio of the microorganism. For instance (Scheme 11), the allylic alcohol ( 14) is reduced to the corresponding saturated compound in high yield and optical purity (though in a slow reaction) via the intermediacy of the corresponding enal and (S)-2-benzyloxymethylpropanal [53] . Historically the biotransformations of cyclic enones have been important, not least Leuenberger's transformation of the appropriate cyclohexenedione into the saturated ketone (15), a precursor for tocopherol [54] .…”

“…Copper(II)-bis(oxazoline) complexes (48) hydrolysis, oxidation and reduction optically active cannabinols, Evans and co-workers showed that an acyclic dienol ester combined with the amide (53) to give the cyclohexane derivative (54) (Scheme 47) [135] . The phosphino-oxazoline copper(II) complex (55) has also been found to be an effective catalyst [136] as have some titanium complexes, such as the extensively researched titanium±TADDOL system (56) [137] .…”

“…30 (2 H, m), 1.72±1. 53 (3 H, m), 2.17 (1 H, m), 2.89±2. 79 (3 H, m), 3.17 (1 H, dd, J 10.7, 8.2 Hz), 3.40 (1 H, dd, J 10.7, 5.4 Hz) and 3.43 (1 H, br s).…”

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“…331 The apparent baker's yeast-catalyzed stereoselective reduction of the C᎐ ᎐ C double bond of an allylic alcohol probably proceeded via the enal. 332 Aryl azides, 333 aromatic N-oxides 334 , azide over aldehyde reduction 335 and even unusual Ar-C᎐ ᎐ C bond reductions 336,337 have been demonstrated using baker's yeast or enzymes isolated from it. Sulfoxides can be reduced stereoselectively using Rhodobacter sphaeroides.…”