Enantioselective Flow Synthesis of Rolipram Enabled by a Telescoped Asymmetric Conjugate Addition–Oxidative Aldehyde Esterification Sequence Using <i>in Situ</i>-Generated Persulfuric Acid as Oxidant
作者:Bence S. Nagy、Patricia Llanes、Miquel A. Pericas、C. Oliver Kappe、Sándor B. Ötvös
DOI:10.1021/acs.orglett.1c04300
日期:2022.2.4
A novel approach is reported for the enantioselective flow synthesis of rolipram comprising a telescoped asymmetric conjugate addition–oxidative aldehyde esterification sequence followed by trichlorosilane-mediated nitro group reduction and concomitant lactamization. The telescoped process takes advantage of a polystyrene-supported chiral organocatalyst along with in situ-generated persulfuric acid
1-hydroxy-4(3-cyclopentyloxy-4-methoxyphenyl)-2-pyrrolidone and
申请人:Orion-yhtyma Oy
公开号:US05356923A1
公开(公告)日:1994-10-18
##STR1## Substituted cyclic hydroxamic acids of general formula (I) in which R.sub.1, R.sub.2 and R.sub.3 are independently hydrogen, halogen, lower alkyl, lower alkoxy, cycloalkoxy, aryloxy which is optionally substituted by 1 to 3 halogen, or aralkyloxy, which is optionally substituted by 1 to 3 halogen, or R.sub.1 and R.sub.2 together form a --O--CH.sub.2 --O-- group; with the proviso that R.sub.3 is not hydrogen when R.sub.1 and R.sub.2 are both hydrogen; R.sub.4 and R.sub.5 are independently hydrogen or lower alkyl, R.sub.6 is hydrogen or lower alkyl and physiologically acceptable salts and esters thereof are selective inhibitors of phosphodiesterase IV activity and leukotriene B.sub.4 and C.sub.4 synthesis without showing any significant effect on phosphodiesterase III activity, and are therefore useful in the treatment of hypersensitivity and inflammatory diseases.
Bifunctional Iminophosphorane‐Catalyzed Enantioselective Nitroalkane Addition to Unactivated α,β‐Unsaturated Esters
作者:Daniel Rozsar、Alistair J. M. Farley、Iain McLauchlan、Benjamin D. A. Shennan、Ken Yamazaki、Darren James Dixon
DOI:10.1002/anie.202303391
日期:——
The first intermolecular enantioselectiveaddition of nitroalkanes to unactivated α,β-unsaturated esters is described, catalyzed by a bifunctional iminophosphorane (BIMP) superbase. This fundamental synthetically relevant transformation proceeds with high enantiomeric excesses and yields over a wide range of feedstock substrates, providing pharmaceutically relevant building blocks in a single step