Kh. Park et H. Rapoport, ENANTIOSELECTIVE SYNTHESIS OF (1R,4S)-1-AMINO-4-(HYDROXYMETHYL)-2-CYCLOPENTENE A PRECURSOR FOR CARBOCYCLIC NUCLEOSIDE SYNTHESIS, Journal of organic chemistry, 59(2), 1994, pp. 394-399
(1R,4S)-1-Amino-4-(hydroxymethyl)-2-cyclpentene, an important precurso
r for the synthesis of carbocyclic nucleosides, has been prepared from
D-glucono-delta-lactone in enantiomerically pure form (er > 99/1). Th
e synthesis proceeded from the lactone via the diisopropylidene-2-amin
o-2-deoxymannonate and hydrolysis of the terminal isopropylidene group
. Selective oxidation of the primary alcohol and esterification gave t
he corresponding mannarate which was deoxygenated at C5. Further trans
formations by regiospecific eliminative cleavage of the ketal and hydr
ogenation gave dimethyl (2S,3R)-2-amino-3-hydroxyadipate. Dieckmann cy
clization through specific carbanion formation at C5 led to the aminoh
ydroxy(methoxycarbonyl)cyclopentanone which was readily converted in a
series of high-yielding steps to the target cyclopentene. Throughout
the synthesis, stereo- and regioselectivities were strongly influenced
by the sterically demanding 9-phenyl-9-fluorenyl protecting group on
nitrogen.