One-pot chemoenzymatic synthesis of protected cyanohydrins

In a chemoenzymatic one-pot reaction of ethyl cyanoformate with benzaldehyde catalyzed by the hydroxynitrile lyase from Prunus amygdalus ethoxycarbonylated (R)-mandelonitrile is formed in a highly enatioselective manner. The reaction was performed both in aqueous and organic media. ¹H NMR investigations revealed a two-step procedure consisting of an enzyme-catalyzed addition of HCN, generated by hydrolysis of ethyl cyanoformate, to the aldehyde followed by ethoxycarbonylation of the free cyanohydrin in a second step     

Iron(III) triflate-catalyzed one-pot synthesis of acetal-type protected cyanohydrins from carbonyl compounds

A variety of cyanohydrin THP ethers were readily prepared from carbonyl compounds with trimethylsilyl cyanide and tetrahydropyran-2-yl acetate under the influence of a catalytic amount of iron(III) triflate in a convenient one-pot procedure. This method was also effective to prepare O-protected cyanohydrins by various acetal-type protective groups.     

A convenient synthesis of biphenylene

An efficient one-pot reaction for the synthesis of biphenylene 1 starting from biphenyl is reported. The final product was prepared from commercially available, cheap materials in moderate yet very competitive yield. Biphenyl was ortho-lithiated to 2,2′-dilithiobiphenyl 2, which was then coupled to biphenylene.     

A convenient synthesis of geiparvarin

Acylation of 3-methyl-2,3-bis(trimethylsiloxy)-l-butene (PhLi) with (E)-2-methyl-2-butenoyl chloride gives the corresponding 3(2H)-furanone derivative, which can be readily converted to the naturally occurring antitumor agent Geiparvarin by two steps.     

A convenient synthesis of bis-dialkylaminoacetylenes

The novel compounds tris-diethylaminocyclopropenyl perchlorate, bis-diethylaminocyclopropenone, and bis-dimethylaminocyclopropenone have been made. Pyrolysis of the cyclopropenones affords bis-dimethylamino- and bis-diethylaminoacetylene, and with iron carbonyl these have been converted to iron complexes of tetrakis-dialkylaminocyclopentadienones.     

A convenient synthesis of phenols

Abstract

Anilines are rapidly, often within 60?minutes, converted into the corresponding phenols in up to 87% isolated yield. The presented experimentally simple protocol display broad compatibility with a variety of functional groups, and in particular, well suited for the preparation of methyl-substituted phenols. Such phenols are not easily available by other synthetic approaches. The formation of phenolic radical coupling products was not observed even for activated anilines using this open flask method.     

A convenient synthesis of phosphonothioic acids

A method for the convenient synthesis of phosphonothioates, or phosphonothioic acids, is reported. A significant advantage of the method is the alleviation of the need for purification of intermediates, other than washing with water. No chromatography is needed and the only purification step is the crystallization of the final product. The method uses standard reagents and should be applicable to the synthesis of phosphonothioic acids bearing a range of functional groups.     

A convenient enzymatic synthesis of L-halotryptophans

A scalable and general biotransformation for the generation of a series of L-halotryptophans using the lysate of a commercially available microorganism containing tryptophan synthase.     

A convenient synthesis of 1-triacontanol

1 -Tricontanol, a new plant growth regulator, has been synthesised starting from stearic acid, and by two successive additions of six carbon units through enamine intermediates.     

A convenient synthesis of thiamacrocyclic dilactams

A convenient synthesis of 26‐ to 28‐membered thiamacrocyclic dilactams 8 was achieved via base‐catalyzed condensation reaction of bis‐2‐cyanoacetamides 4 with dialdehyde derivatives 7 . The reaction was assumed to be geometrically stereoselective, affording E, E′‐configuration as the only isolable isomer. N, N′‐[Alkanediylbis(thia‐2,1‐phenylene)]bis[2‐cyanoacetamides] 4 were obtained by the reaction of cyanoacetic acid with the corresponding diamine hydrochlorides 3 . © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:249–254, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20292     

High-throughput synthesis and analysis of acylated cyanohydrins

The yields and optical purities of products obtained from chiral Lewis acid/Lewis base-catalysed additions of alpha-ketonitriles to prochiral aldehydes could be accurately determined by an enzymatic method. The amount of remaining aldehyde was determined after its reduction to an alcohol, whilst the two product enantiomers were analysed after subsequent hydrolysis first by the (S)-selective Candida antarctica lipase B and then by the unselective pig liver esterase. The method could be used for analysis of products obtained from a number of aromatic aldehydes and aliphatic ketonitriles. Microreactor technology was successfully combined with high-throughput analysis for efficient catalyst optimization.