A new norephedrine-derived chiral base for epoxide rearrangement reactions
作者:Simon E de Sousa、Peter O'Brien、H.Christian Steffens
DOI:10.1016/s0040-4039(99)01740-2
日期:1999.11
The conversion of (1R,2S)-norephedrine into a novel chiral diamine (83% yield, simple two step synthesis) and its use as a chiral base in two epoxiderearrangement reactions is reported. Rearrangement of a 4,5-disubstituted cyclohexene oxide and of a 4-aminosubstituted cyclopentene oxide generated allylic alcohols of >90% ee. These results represent the highest levels of enantioselectivity reported
Catalytic enantioselective rearrangement of meso-epoxides mediated by chiral lithium amides in the presence of excess cross-linked polymer-bound lithium amides
作者:Atsushi Seki、Masatoshi Asami
DOI:10.1016/s0040-4020(02)00371-x
日期:2002.6
Insoluble polymer-bound achiral lithium dialkylamides were prepared from the corresponding cross-linked polymer-bound amines and butyllithium. The polymer-bound achiral reagent was applied to a catalytic enantioselective rearrangement of meso-epoxides as an in situ regenerating agent of a chiral lithiumamide. The efficiency of the catalytic system was improved, and chiral allylic alcohol derivatives
(.+-.)-Carbocyclic 5'-nor-2'-deoxyguanosine and related purine derivatives: synthesis and antiviral properties
作者:Sharadbala D. Patil、Masakazu Koga、Stewart W. Schneller、Robert Snoeck、Erik De Clercq
DOI:10.1021/jm00090a007
日期:1992.6
Beginning with 3-cyclopenten-1-ylamine hydrochloride, the 5'-nor derivatives of carbocyclic 2'-deoxyguanosine (2), 2'-deoxyadenosine (3), and 2,6-diaminopurine 2'-deoxyribofuranoside (4) have been prepared. These compounds were evaluated for antiviral potential versus herpes simplex virus, varicella-zoster virus, cytomegalovirus, vaccinia virus, vesicular stomatitis virus, and human immunodeficiency virus and found to lack activity. Also, compounds 2-4 were virtually nontoxic toward the host (human diploid fibroblast ESM and HEL) cells. These biological properties may be due to the inability of 2-4 to be phosphorylated to the requisite nucleotide level that is likely to be necessary for biological activity by correlation to carbocyclic 2'-deoxyguanosine (1), which possesses significant antiviral properties as a result of conversion to its 5'-triphosphate derivative.
Synthesis and enantioselective rearrangement of 4-amino-substituted cyclopentene oxides
作者:Peter O'Brien、Timothy D. Towers、Matthias Voith
DOI:10.1016/s0040-4039(98)01821-8
日期:1998.10
Several N-mono- and diprotected alkenes have been prepared and the, stereoselectivity of their epoxidation has been investigated: N-monoprotected alkenes give cis epoxides preferentially (due to hydrogen bonding directed epoxidations) whereas N-diprotected alkenes produce trans epoxides exclusively (due to steric effects). Chiral lithium amide base-mediated rearrangement of a cis-monoprotected epoxide generated the corresponding amino-cyclopentenol in good yield and with an enantiomeric excess of 60%. (C) 1998 Elsevier Science Ltd. All rights reserved.
KOGA, MASAKAZU;SCHNELLER, STEWART W., TETRAHEDRON LETT., 31,(1990) N1, C. 5861-5864