Chiral glycerol ethers

Scheme 3. Synthesis of chiral glycerol ethers starting from (D)-mannitol (12).

Alkylations of phenols with epichlorohydrin under PTC conditions and microwave irradiation were described twice in 1998. Subsequently, ring-opening reactions of the epoxide group were also performed using microwaves (Eqs. 20 and 21) [31, 32]. In the first catalytic synthesis of chiral glycerol sulfide ethers was described [31] in the second biologically active amino ethers were prepared [32],... 

Figure 10. Preparation of chiral glycerol derivatives and D- and L-glycerol acetonide. a 1. Hj/Pd-C 2. methyl isopropenyl ether/pyridinium p-toluensulfonate 3. K2C03/Me0H...

Already mentioned earlier in this book (see above), raspailynes constitute a series of glycerol enolic ethers, the long-chain enolic part of which is conjugated with an ene-yne system. These unstable derivatives were isolated from the species Raspailia pumila and Raspailia ramosa harvested in Brittany (Bay of Morlaix). There are three series of raspailynes which differ in the stereochemistry of the two double bonds Z,Z (the most common type), Z,E and E,Z (the least common type). In each type the absolute configuration of carbon 2 of glycerol is S, as with all chiral glycerol monoethers encountered so far in marine... 

The 2,7-naphthyridine system 53 (Scheme 8.4.18) was combined with 2,4-dinitrochlorobenzene and 2-amino glycerol for in situ reaction of the resulting Zincke salt. The resulting naphthyridinium 54 was trapped by Bradsher cycloaddition with (Z)-vinyl ether 55, providing tetracycle 56 (X-ray) upon internal addition of one of the diastereotopic hydroxymethyl groups to the resulting iminium. This approach was also extended to the use of chiral 2,7-naphthyridinium salts, prepared via the analogous Zincke process. ... 

Yang and co-workers introduced chirality in their opening sequence by reacting (5)-glycerol acetonide (87) with 2,3,4-trifluoro, 1-nitrobenzene (45) to yield ether 88 (Scheme 4.14) (Yang et al., 1999). Deprotection of the acetonide under standard conditions delivered diol 89, which was treated with hydrogen bromide in acetic acid to give a mixture... 

These ether lipids are all chiral molecules with an R configuration but are derivatives of the nonchiral glycerol. The carbon atoms of glycerol are numbered using the stereochemical system which is described on p. 470. The ether linkage is to the sn-1 carbon atom. Most phospholipids are derivatives of the sn-3 phosphate ester of glycerol. 

Fig. 6.2 The upper part shows schematically the typical feature of a lipid with a polar head and a longer hydrocarbon tail. In row 1, the glycerol with the chiral C-atom marked with an asterisk is esterified with a saturated fatty acid (upper part), and the lower part shows an ester with an unsaturated fatty acid. The polar head here consists of phosphate connected to an amino group. Row 2 presents an ether linkage as it occurs in Archaea...

The synthesis of chiral acyclic nucleosides 276 utilizes the readily available protected acetoxymethyl ether of glycerol 275, which reacted with silylated nucleobases under phase transfer conditions using dibenzo-18-crown-6 to give N-9 purinyl and N-1 pyrimidinyl acyclonucleosides. Removal of the benzoyl groups by methanolic ammonia gave 277 (88JMC144 89TL6165). 

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