D-Threitol

The other tetritols were formerly called d-and /-erythritol, but have been renamed L-and D-threitol respectively. A racemic form can also be prepared,... 

Fig. 1. Stmctures of the tetritols (a) erythritol, (b) D-threitol, and (c) L-threitol and the pentitols (d) ribitol, (e) D-arabinitol, (f) L-arabinitol, and (g) xyhtol.

Hartman and R. Barker synthesized 1,4-anhydroerythritol (3) by the saponification of 1-O-p-tolylsulfonyl-D-erythritol (1). The reaction apparently proceeded by direct reaction of the 4-hydroxyl group with the 1-p-tolylsulfonoxy group, and not through the intermediate formation of the 1,2-anhydride, which would have afforded the epimer, namely, 1,4-anhydro-D-threitol (2). Similarly, 1-O-p-tolylsulfonyl-D-threitol gave 1,4-anhydro-D-threitol (2). 

However, saponification of 2-O-p-tolylsulfonyl-L-erythritol or of 2-O-p-tolylsulfonyl-D-threitol did not furnish any 1,4-anhydro compounds, but only the respective tetritol. 

Esterification of 622, and reaction of the ester with acetone furnished 623, which was reduced to 4-deoxy-2,3-0-isopropylidene-D-threitol (624). This substrate was further employed332 for the synthesis... 

The 2 + 2-cycloaddition of chlorosulfonyl isocyanate with chiral alkoxyallenes, derived from ethylidene and benzylidene L-erythritol and D-threitol, produces azetidi-nones that are readily converted into the corresponding tricyclic cephams. NMR and CD spectroscopy were used to assign the absolute configurations of the azetidinones... 

Glycol cleavage of diacetamides proceeds smoothly and without apparent attack on the fV-substituted carbon atom,44 1, l-bis(acetamido)-l-deoxy-D-erythritol and -D-threitol giving rate curves similar to that of glyceritol. Rate curves for pentitol diacetamides resembled those of eryth-ritol. 

Fig. 3 Chiral bases used to carry out enantioselective MTO-catalyzed oxidation chemistry Troger s base (a), R-(+)-l-phenylethylamine (b), lrans-( 1 R,2R)-1,2-diaminocyclohexane (c), tra s-iV-(2-hydroxycyclohexyl)pyrazole (d), and (—)-2,3-0-isopropylidene-D-threitol (e)...

Chiral alkoxy allenes derived from 1,3-alkylidene-L-erythritol and -D-threitol have been used in cycloaddition reactions to provide the 4-substituted /3-lactams 418 (R = Me, Ph). Intramolecular alkylation at nitrogen was achieved by the action of potassium carbonate and tetrabutylammonium bromide in dry acetonitrile. The absolute stereochemistry of the product 419 (R = Me, Ph) was assigned on the basis of the CD helicity rule (see Section 2.04.3.5) and NMR spectroscopy. The [2+2] cycloaddition of CSI to threitol vinyl ethers was found to have low stereoselectivity in contrast to the findings with erythritol derivatives <2004CH414, 2005EJ0429>. 

Benzylidene-D-threitol (VII) was prepared by Haskins, Hann and Hudson79 by hydrogenation of 2,3-benzylidene-D-threose, a product of the periodate oxidation of 2,3-benzylidene-D-arabitol. The tetritol was proved to be D-threitol, rather than erythritol, by the fact that hydrolysis of VII and subsequent treatment with benzaldehyde afforded the known dibenzylidene-D-threitol. The acetal group was allocated to the 2,3-position on the basis of independent evidence concerning the structure of the parent benzylidene-D-arabitol (see page 152). For the physical constants of acetals of threitol see Table VIII. 

An interesting templated bis-functionalization was reported by Shinkai and co-workers who introduced two boronic acid groups regio- and diastereo-selectively into C6o by using saccharides or saccharide derivatives as imprinting templates.147-149 Thus, when D-threitol was used as the template, C2-symmetric cis-3 isomers fC-49 and fA-49,150 were obtained in a nearly. 72 28 ratio after removal of the saccharide templates (Scheme 1.6).149 Competitive complexation studies indicated that D-threitol-imprinted boronic acid (fC)-49 and L-threitol-imprinted (A)-49 preferentially rebind their original templates with up to 48% d.e.148 Exploration of other regio- and diastere-oselective double [4 + 2] cycloadditions between C6o and o-quinodimethanes... 

A polyoxometalate is also at the heart of an enantioselective epoxidation of allylic alcohols using a C-2 symmetric chiral hydroperoxide 39 derived from l,l,4,4-tetraphenyl-2,3-0-isopropylidene-D-threitol (TADDOL). Thus, in the presence of the oxovanadium(IV) sandwich-type POM [ZnW(V0)2(ZnW9034)2]12- and stoichiometric amounts of hydroperoxide 39, the dienol 40 is converted to the (2R) epoxide 41 in 89% yield and 83% ee. The proposed catalytic cycle invokes a vanadium(V) template derived from the POM, substrate, and hydroperoxide, a hypothesis supported by the lack of enantioselectivity with unfunctionalized alkenes. The catalytic turnover is remarkably high at about 40,000 TON <03OL725>. 

---