A few characteristic data of the compounds (1 l ) , (1 2), and ( 14)-( 17) are collected in Table 2. Apart from the diastereomerism caused by the methoxyethyl protecting group in (13), (16a), and (17), the compounds are, according to the IHand I3C-NMR spectra, diastereomerically pure and thus in the present case also enantiomerically pure; we have prepared (11) and (14) in both enantiomeric forms. Table 2. Characteristic physical data of the compounds 1/11. (12).
(14)-(17) obtained from (R,R)-tartaric acids. 'H-NMR, "C-NMR, IR, and MS data are consistent with the given structures. B.P.. M.p., Spec. Rotation ( c = l , CHCI,) 130 "C/O.O1 torr [a];;= +13.5" [a]:;= -12.5" [from (S,S)-tartaric acid] 72-73 "C [ a ] g = +2.8" (a]:= -10.5" 75"C/0.05 tom [u]:'=+17.7" 75 "C/O.O5 torr [a]E= -14.0" 53-54 "C [a]:= -18.4" 'H-NMR (CDCl,), 6-values, coupling constants [Hz] 4.55 (% CHZPh), 3.08 (4. J = 4 , 3-H), 2.4 (d, J= 6, OH [a]) 5.16 (q, J=5, 2-H), 2.82 (m, 2 4-H) 4.55(s,CH,Ph),2.9-3.15(m,3-H),2.34(d, J = 4 , OH [a]) 4.4 and 4.3 (AB, J= 12, CH,Ph), 2.66 (q x d, 4.4 and 4.33 (AB, J = l I , CH,Ph), 2.54 (9 x d, Jq=S.5, J,=2, 3-H) [b] 4.54 (s, CH2Ph), 3.1-3.4 (m, 2 OH [a]), 1.25 (5, N(CH3)d 4.51 (s, CH2Ph), 2.6 (d, J = 7 , OH [a]) 4.52 (s, CH>Ph), 3.3 and 3.28 (each 1 s, OCH, (diastereomeric ratio 1 :l)), 3.15 (d, J= 4) and 3.06 (d, J = 5, OH [a]), 1.65 (s, 3 6-H) Jq=5.S, Jd=4, 3-H) [b]
[a] Exchangeable with D20.
[b] 360-MHz 'H-NMR spectra in CDCI, and in CaD6 were also recorded.
Through the reagents described here the enantiomeric tartaric acidsI'l have become a versatile source of chirality. In contrast to the carbohydrates generally employed so far (see references cited in Is]) inexpensive tartaric acid has only two types (C, axis!) of functional groups, whose number can be readily doubled [see (I), (2)]; moreover, a C4 unit can be incorporated with less effort into a greater number of target molecules than a C6 building block.