Baba, Naomichi

Inouye, Yuzo

Oda, Jun'ichi

Kyoto University Research Information Repository

TitleAddition Effect of Some Macrocyclic Polyethers on the Asym-metric Reduction with Chiral NADH Model Compounds(Commemoration Issue Dedicated to Professor Yuzo Inouye onthe Occasion of his Retirement)Author(s)Baba, Naomichi; Oda, Jun'ichi; Inouye, YuzoCitationBulletin of the Institute for Chemical Research, KyotoUniversity (1983), 61(2): 113-116Issue Date1983-08-15URL http://hdl.handle.net/2433/77026RightType Departmental Bulletin PaperTextversionpublisherKyoto UniversityBull. Inst. Chem. Res., Kyoto Univ., Vol. 61, No. 2, 1983  11111111111111111111111111 NOTE nnuauuuuuuuuw  Addition Effect of Some Macrocyclic Polyethers on the Asym-   metric Reduction with Chiral NADH Model Compounds             Naomichi BABA*, Jun'ichi ODA*, and Yuzo INOUYE*                               Received April 14, 1983    As reported in our previous publications dealing with an NADH model reaction,') dependence of enantiomeric excess (e.e.) on the reaction conversion and addition effect of the oxidized form on the product stereochemistry were found to appear notably with the chiral 1, 4-dihydronicotinamide carrying polar functional groups. The phenomenon has been explained in terms of stereochernical participation of oxidized form of the remaining reductant. A later study concerning this problem showed that asymmetric reduction of ethyl benzoylformate with a chiral dihydronicotinamide was significantly affected also by aromatic additives capable of exerting an attractive inter-action with dihydropyridine molecules, which was further consolidated by the chelation of the hydroxyl groups with magnesiuin.2) This finding and a working-hypotheses suggested that some sterochemically bulky compounds which may not be necessarily aromatics but have chelation site(s) with metals and/or inclusion capability of metals may also render chiral dihydropyridines more stereoselective toward prochiral sub-strate. So that a series of asymmetric reductions of ethyl benzoylformate were per-formed with the NADH models 1 and 2 in the presence of additives given below.                                                              H.,,H    CON~/ CON N HmNH2IIH" CH2OH     CH2PhCH2Ph  12                                 Structure of 1 and 2    Typically, a solution of the model 1 (0.165 g, 0.5 mmol), dry magnesium perchlorate (0.078 g, 0.35 mmol), ethyl benzoylformate (0.089 g, 0.5 mmol) and [2.2.2]-cryptand (0.066 g, 0.175 mmol) in dry acetonitrile (5.0 ml) was stirred at room temperature for 16 h. Usual work-up and isolation afforded pure ethyl mandelate. Chem. yield, 41.4%, [a],i°, —94.9°(R) (c 0.840, EtOH). 90.9%e.e. * ,~J * NEE-, 4±i1 E: Laboratory of Plant Product Chemistry, Institute for Chemical    Research, Kyoto University, Uji, Kyoto 611. (113)                                 N.  BABA,  J.  ODA,  and  Y.  TNOUYE              H~000--)           ~~-J~NH H~~JNH [2.2.2]-cryptand[2 .2. 1] -cryptand / \    HN0l/--\000         NH-0 0J\\--/H.0p• \_J quinaldine t.,,,,,0 J 1,10-diaza-18-crown-6 dibenzo-18-crown-6                                 Structure of additives    Table. Asymmetric Reduction of Ethyl Benzoylformate with the Models 1 and 2 in the            Presence of the Additives                                                           additive subst. chem.  run NAH Mg(C104)2 Mg/NAH additive %e.e.    (mmol) (mmol)NAH NAH yield     1 1 (0.5) 0.35 0.7 [2.2.2]-cryptand 0.036 1.00 57.5 77.5    2 1 (0.5) 0.35 0.7 [2.2.2] 0.175 1.00 58.6 84.2    3 1 (0.5) 0.35 0.7 [2.2.2] 0.350 . 1.00 41.4 90.9    4 - 1 (0.5) 0.35 0.7 [2.2.2] 0.600 1.00 43.1 89.0    5 1 (0.5) 0.35 0.7 [2.2.2] 0.800 1.00 43.1 88.0    6 1 (0.5) 0.35 0.7 [2.2.2] 1.000 1.00 29.1 89.6   7 1 (0.5) 0.35 0.7 none0 1.00 75.1 72.7    8 1 (0.5) 0.35 0.7 [2.2.2] 0.35 0.20 43.4 90.6   9 1 (1.0) 0.8 0.8 none0 0.20 100 53.6   10 2 (0.4) 0.28 0.7 [2.2.2] 0.35 1.00 41.9 33.8.   11 2 (0.6) 0.48 0.8 none0 1.00 54.9 54.5   12 1 (0.5) 0.35 0.7 [2.2.1] 0.35 1.00 16.2 61.3   13 1 (0.5) 0.70 1.4 [2.2.1] 0.35 1.00 62.0 58.4    14 1 (0.5) 0.35 0.7 1, 10-diaza-18-crown-6 0.35 1.00 46.5 89.2    15 1 (0.5) 0.70 1.4 1, 10-diaza-18-crown-6 0.35 1.00 70.6 76.5   16 1 (0.5) 0.35 0.7 quinaldine 0.35 1.00 43.2 67.1   17 1 (0.5) 0.70 1.4 quinaldine 0.35 1.00 56.5 41.6    18 1 (0.5) 0.35 0.7 dibenzo-18-crown-6 0.35 1.00 44.9 80.1    19 1 (0.5) 0.70 1.4 dibenzo-18-crown-6 0.35 1.00 44.9 43.6    As can be seen from the experimental data in Table and Figure, the new findings in the present study can be summarized as follows.    (i) In the reduction with the model 1, [2.2.2]-cryptand improved the e.e. with highest extent among the additives under the condition of additive/NAH=0.35 and Mg(C104)2/NAH=0.7 (Compare runs 3, 7, 12, 14, 16 and 18). (114)             Addition Effects of Polyethers on the Asymmetric NADH Model Reductions                 %e.e.  90-• ^ ^ ^ • 80- / • • 70-~                 3.6 17.5 35 50 60 80 100% [2 .2 . 2] —cryptand/1             Figure. Change of %e.e. on the Varying Amount of [2.2.2]-cryptand in the                     Asymmetric Reduction of Ethyl Benzoylformate with the Model 1.      (ii) 1, 10-Diaza-18-crown-6 was also a good additive (run 14), however, the others  were ineffective or rather reduced the e.e. in some cases (runs 12 and 16) comparing with  the value obtained in the absence of additives (72.7% in run 7) .     (iii) The maximum e.e. was obtained at the concentration of 35 mol % to the NAH 1 and the e.e. was nearly constant thereafter.      (iv) In the asymmetric reduction with the prolinol model 2, the addition of   [2.2.2]-cryptand rather lowered the e.e. (runs 10 and 11) by about 20%.       (v) As already reported, the product stereochemistry in the present asymmetric   reduction was found to depend on the initial concentration of the substrate. For ex-  ample, as run 9 shows, when the substrate concentration was 20 mol % relative to the   model 1, the e.e. was only 54%. However, in the presence of 35 mol% of [2.2.2]-  cryptand the e.e. increased up to 90% (run 8) .      Thus the effect of [2.2.2]-cryptand for improving the e.e. was unequivocally   demonstrated for the first time. From the foregoing, the product stereochemistry  seems to be sensitively influenced by the symmetry, molecular size and sort of hetero-  atoms of the additives. Also included is an interesting result that by the addition of   [2.2.2]-cryptand the low e.e. observed at the low concentration of the substrate3) was   strikingly improved indicating that the cause of the low e.e. was successfully eliminated  by the additive.      Although the mechanistic explanation for the addition effect presented here is  still obscure, the stereochemical outcome suggests much better chiral or achiral additives  for NADH model reactions to exist.                          MATERIAL ANDMETHOD       [2.2.1]-, [2.2.2]-Cryptands and 1, 10-diaza-l8-crown-6 were purchased from  Aldrich Co Ltd. Dibenzo-18-crown-6 was kindly offered by Dr. Nobuharu Ando in (115)                                   N. BABA, J. ODA, and Y.  INOUYE    our laboratory. Preparations and physical properties of the NADH models 1 and 2    will be described elsewhere.4) The general procedure for the asymmetric reductions    were just as exemplified typically in preceding. The percent e.e. of the product    mandelate were determined from its optical rotation in ethanol which was recorded on    Perkin-Elmer 241 polarimeter. Shimadzu gaschromatograph GC-4CM with 5%-    polyethylene  glycol succinate was used for determination of chemical yield and con-   centration of the sample solution for the optical measurement.                           ACKNOWLEDGMENT      This work was supported in part by a grant in aid (57560125) from the Ministry    of Education of Japan to which we are deeply grateful.                                 REFERENCE (1) T. Makino, T. Nunozawa, N. Baba, J. Oda, and Y. Inouye, J. Chem. Soc. Perkin Trans I, 7, 1980. (2) T. Makino, T. Nunozawa, N. Baba, J. Oda, and Y. Inouye, Tetrahedron Lett., 1683, 1979. (3) N. Baba, J. Oda, and Y. Inouye, Angew. Chem., 94 465 (1982). Int. Ed. Engl., 21, 433. (4) It is being presented in a paper prepared for the dependence of product stereochemistry on the           initial concentration of substrate in asymmetric reductions with chiral NADH model compounds. (116)

Addition Effect of Some Macrocyclic Polyethers on the Asym-metric Reduction with Chiral NADH Model Compounds (Commemoration Issue Dedicated to Professor Yuzo Inouye on the Occasion of his Retirement)

http://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/77026/1/chd061_2_113.pdf

Addition Effect of Some Macrocyclic Polyethers on the Asym-metric Reduction with Chiral NADH Model Compounds (Commemoration Issue Dedicated to Professor Yuzo Inouye on the Occasion of his Retirement)

Abstract

Similar works

Full text

Available Versions

Kyoto University Research Information Repository