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A new synthetic route of to pharmaceutical intermediates (S)-1a–b and (S)-14 is reported. The reaction pathway is based on the baker’s yeast-mediated reduction of the α-alkoxy cinnamaldehydes 9a–c to give the corresponding (S)-alcohols in good yields and excellent ee.

A new scaleable synthetic route to the title compounds has been developed. The reaction pathway is based on the α-chymotrypsin-catalysed hydrolysis of the racemic ethyl 2-ethoxy-3-( p -methoxyphenyl)propanoate or of the racemic ethyl 2-methoxy-3-( p -methoxyphenyl)propanoate to give the corresponding resolved ( S )-esters with excellent ee. The acids were easily separated from the ( S )-esters by a simple acid–base work-up. The overall yields of 1 and 2 were 16% and 17%, respectively.

The enantiomers of methyl ionones 1 and 2 were prepared by an enzyme-catalysed approach. Their odour properties were evaluated by skilful perfumers.

An enantioselective baker’s yeast mediated approach to the pharmacologically active ( R )-enantiomer of Tamsulosin hydrochloride is reported.

A study on the synthesis of the isomers of the natural C-13 norterpenoids derivatives 7,11-epoxymegastigma-5(6)-en-9-one and 7,11-epoxymegastigma-5(6)-en-9-ols is reported. The latter compounds were prepared from readily available racemic alpha-ionone and then resolved by mean of lipase-mediated acetylation. The obtained enantiomerically forms were evaluated for their odour properties. (C) 2005 Elsevier Ltd. All rights reserved.

An enantioselective synthesis of cis -7-methoxy-calamenene 1 has been accomplished through the following key-steps: (i) enzymatic resolution of the racemic allyl alcohol 3 to furnish the ( R )-enantiomer (ee >99%); (ii) Claisen-orthoester rearrangement of 4 to introduce the isopropyl unit on the benzylic position (99% ee); (iii) diastereoselective reduction of dihydronaphthalene derivative 11 to give the cis -isomer 12 (98% de); (iv) regioselective introduction of the formyl group by a Vilsmeier reaction followed by reduction to give 1 .

A study on the enzymic resolution of the most common p-menthan-3-ol monoterpene isomers is described. Enantioenriched alcohols 1, 5, 10, 11 and 12 are obtained by means of the lipase-mediated kinetic acetylation of the corresponding racemic materials. The stereochemical aspects of the enzymic process have been investigated. We found that the structural features of the starting p-menthan-3-ol as well as the kind of lipase used, impacted strongly on the enantioselectivity of the resolution. The potentialities of this approach for preparative purposes are discussed.

The Johnson–Claisen rearrangement of enantiopure allylic alcohols in triethylorthopropionate is the key step for the preparation of chiral molecules with benzylic stereogenic carbon atoms bearing an isopropyl moiety. The synthetic procedure is applied to the preparation of ( R )- and ( S )-3-methyl-2-phenylbutylamine.

The two enantiomers of the floral odorant Florhydral® were prepared by enzymatic methods, and their olfactory properties were evaluated. (+)-Florhydral® was found to be much more powerful than the (−)-enantiomer.

The first enantioselective synthesis of natural (−)-cis-Aerangis lactone (−)-1a and its (+)-trans-diastereoisomer (+)-1b is described. The key steps in the synthesis are: (i) the enantiospecific and 100% diastereoselective baker's yeast reduction of 1,4-keto acid 2, to afford enantiopure trans-cognac lactone (+)-10; (ii) the regioselective PPL-mediated hydrolysis of the primary acetate moiety of diacetate (+)-(3S,4R)-3, obtained from (+)-10. Chain elongation by one carbon atom via cyanide substitution, and inversion of the configuration of C(5) in nitrile derivative (+)-21a are also required to complete the synthetic route to (−)-1a.

A three step synthesis of (R)-(−)-baclofen is described. The key step is the orthoester Claisen rearrangement of enantiopure allylic alcohol (S,E)-(−)- 1a , affording γ,δ-unsaturated ester (S,E)-(+)- 6 with high stereoselectivity. This latter derivative is converted into ( R )-(−)-baclofen through a high yield one-pot reaction.

Two enantiomers of Undecavertol® were prepared by enzymatic methods and their odour properties evaluated.