Hept-2-enose

Interaction of 4,5 6,7-di-0-cyclohexylidene-2,3-dideoxy-l-C-phe-nyl-L-arafeino-hept-2-enose (65) with phenylmethylenetriphenylphos-phorane was accompanied9 6 by the formation of triphenylphosphine, instead of the expected triphenylphosphine oxide, thus indicating the abnormal character of this reaction. This result may be interpreted as involving possible addition of the phosphonium ylide to the alkenic bond, with subsequent stabilization of the intermediate betaine 82 through elimination of triphenylphosphine, and closure of the three-membered ring2(f) with formation of the cyclopropane derivative 83, as shown in equation 5. 

The conversion of acetylated 2,3-dideoxy-hex-2-enoses into acyclic allylamines via acetoxydienal mixtures has been reported (Scheme 4). In a similar way (2E)-4, 6,7-tetra-0-acetyl-2,3-dideoxy-aWeAy-D-[Pg.151]

The intramolecular nitrone-alkene cycloaddition (INAC) of hept-6-enoses 110 can proceed either via the exo-mode to give fused isoxazolidines 111 or the endo-mode to give the bridged 1,2-oxazocines 112 (Scheme 23). 

The cyclopentane-based phosphate 79, designed as a mimic for myo-inositol 1,4,5-trisphosphate, has been synthesized by two different routes. The cyclitol ring was formed firstly by a Cp2Zr induced ring contraction of a hept-6-enose derivative, essentially as previously reported (Vol. 29, p. 238, ref. 94) secondly by a samarium diiodide promoted pinacol-like coupling of a 1,6-dialdehyde derived from methyl 2-0-benzyl-3,4-bis-(p-methoxybenzyl)-a-D-g/wco-hexodialdopyrano-side. ... 

The nitrone, oxime and nitrile oxide cycloadditions to D-ido hept-6-enose and its D- u/o-isomer have been used in the preparation of aminocylitols (65) and (66) as... 

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. 

Hie dipolar cycloaddition of nitrile oxides to terminal sugar alkenes (see VoL 23, Chapter 10, Scheme 18 Vol. 25, Chapter 2, Scheme 11) has been tqiplied to the preparation of the u-gfyeero-D-ga/ocio-configuiated isoxazolines 38 from hept-6-enose 37, and two methods for the chain-extension of primary iodides, both presumed to involve radical mechanisms, have been reported examples are given in Schemes S and 6. ... 

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