Oxetanocin, synthesis

Cyclopentane and Cydobutane Derivatives. - A review of applications and mechanistic aspects of the CpiZr induced direct ring contraction of hept-6-enose and hex-5-enose derivatives to cyclopentane and cyclobutane ring systems with emphasis on the application to oxetanocin synthesis has appeared. (See also Vol. 

Chiral cyclobutanes can be prepared by cycloaddition of alkenes substituted with one or more chiral auxiliary groups. A diastereofacial selectivity of 95% was observed in the diethylalu-minum chloride catalyzed cycloaddition of 1,1-dimethoxyethene (36) with ( — )-dimenlhyl-3-yl fumarate (37).16 The chiral cyclobutane 38 has been used as an intermediate in the synthesis of carbocyclic oxetanocin analogs. 

A total enantioselective synthesis of antiviral carbocyclic oxetanocins 289 and 290 was also completed by the Ichikawa group by utilizing a... 

Hsiao, C.-N. et al. Efficient Syntheses of Protected (2S,3S)-2,3-Bis(hydroxy-methyl)cyclobutanone, Key Intermediates for the Synthesis of Chiral Carbocyclic Analogues of Oxetanocin. 4.1 1990 [127]... 

Synthesis of oxetanocine, a nucleoside antibiotic with anti-HIV action, and of related compounds 91YGK670. 

Asymmetric [2 + 2] cycloaddition reaction affords a practical means of synthesis of optically active cyclobutanes, which can be used as useful intermediates in organic synthesis [138]. Narasaka reported that asymmetric [2 -i- 2] cycloaddition between acryloyl oxazolidinone derivatives and bis(methylthio)ethylene proceeded with high enantios-electivity when catalyzed by TADDOL-derived titanium complex (Sch. 58) [139]. The cyclobutane product was transformed into carbocyclic oxetanocin analogs or (-n)-grand-isol [140]... 

The cleavage of a terminal )3-phenylsulfonyl silyl group to give a methylenecyclopropane is readily accomplished by treatment with tetrabutylammonium fluoride (TBAF) in tetrahydro-furan. Thus, the bis(benzyl) ether of trani-3-methylenecyclopropane-l,2-dimethanol, trans-, 2-bis[(benzyloxy)methyl]-3-methylenecyclopropane (2), was obtained in 91% yield as part of a synthesis of oxetanocin. ... 

The synthesis of cyclobut-A (113), a nucleoside analogue of the potent antiviral antibiotic oxetanocin, was accomplished using intramolecular [2 + 2] cycloaddition catalysed by Cu(I) ions.711 An inseparable mixture of four (E, Z, syn, anti) isomers of 114 was obtained in 70% chemical yield by irradiation of a triene 115 (Scheme 6.48). The nucleoside connection was then established via nucleophilic substitution of an acetate group by adenine and other transformations in several steps. 

Oxetanocins. Oxetanocin A (49), formerly oxetanocin, is the first naturally occurring oxetanose derivative and is isolated from bacillus megaterium (1,145). It inhibits gram-positive bacteria, herpes viruses, and human immunodeficiency virus (HIV) (146). The chemical synthesis of (49) and several derivatives has been reported (147). 

Fenoglio, L, Nano, G.M., Vander Velde, D.G., and Appendino, G., Chemistry and occurrence of taxane derivatives. XXV. Synthesis of azetidine-type taxanes. Tetrahedron Lett. 37 (18), 3203, 1996. Hoshino, H., Shimizu, N., Shimada, N., Takita, T., and Takeuchi, T., Inhibition of infectivity of human immunodeficiency virus by oxetanocin, J. Antibiot. 40 (7), 1077, 1987. 

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