93381-28-3Relevant articles and documents
A scalable, Nonenzymatic synthesis of highly stereopure difunctional C4 secondary methyl linchpin synthons
Mekala, Shekar,Hahn, Roger C.
, p. 1610 - 1617 (2015/02/19)
In response to the continuing widespread use of heterodifunctional C4 secondary methyl building blocks in asymmetric synthesis, we have developed a mole-scale, two-step synthesis of a 1:1 mixture of the diastereomers of 3-bromo-2-methyl-1-propyl camphorsulfonate (casylate). One isomer (2S) has been crystallized to >99:1 dr in ～25% yield. Equilibration of the mother liquor (enriched in 2R) to a 1:1 mixture and recrystallization significantly raises the overall yield of 2S. Applications of 2S include chemoselective Grignard coupling, enabling the very short synthesis of highly stereopure long-chain natural products containing remote, methyl-bearing stereogenic centers [e.g., (R)-tuberculostearic acid], with complete control of configuration. Also, Ag-mediated, completely chemoselective Br displacement from 2S leads to a range of >99:1 er difunctional synthons. Both applications incorporate concurrent recovery of CasO. The enantiomer of 2S can be made from commercial (1R)-10-CasOH.
Haloalkane dehalogenase catalysed desymmetrisation and tandem kinetic resolution for the preparation of chiral haloalcohols
Westerbeek, Alja,Van Leeuwen, Jan G.E.,Szymański, Wiktor,Feringa, Ben L.,Janssen, Dick B.
experimental part, p. 7645 - 7650 (2012/09/21)
Six different bacterial haloalkane dehalogenases were recombinantly produced in Escherichia coli, purified, and used to catalyse the conversion of prochiral short-chain dihaloalkanes and a meso dihaloalkane, yielding enantioenriched haloalcohols. A two-reaction one-enzyme process was established in which the desymmetrisation of a dihaloalkane is followed by kinetic resolution of the chiral haloalcohol that is produced in the first step. In case of 1,3-dibromo-2-methylpropane and 1,3-dibromo-2-phenylpropane, an increase of the enantiomeric excess of the respective haloalcohol was observed in time, leading to ee values of >97%, with analytical yields of 24 and 52%, respectively. The results show that haloalkane dehalogenases can be used for the production of highly enantioenriched haloalcohols and that in some cases product enantiopurity can be improved by allowing a two-step one-enzyme tandem reaction.
Ethyl phenylsulfinyl fluoroacetate, a new and versatile reagent for the preparation of α-fluoro-α,β-unsaturated carboxylic acid esters
Allmendinger, Thomas
, p. 4905 - 4914 (2007/10/02)
The title compound 2 can be alkylated with a wide range of alkyl halides and Michael acceptors. Subsequent thermal elimination of phenyl sulfinic acid 3 leads to α-fluoro-α,β-unsaturated ethyl carboxylates 5 and 10, an important class of intermediates for fluorine containing biologically active compounds.
