An Enantioselective Formal Synthesis of Montelukast Sodium
A formal synthesis of the antiasthma drug montelukast sodium is described, wherein the key chiral diol intermediate was accessed with greater convergence of the C–C bond-forming steps as compared to previous routes. Improved synthetic efficiency was achieved by deploying homogeneous metal-based cata...
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Published in | Journal of organic chemistry Vol. 80; no. 8; pp. 3891 - 3901 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
WASHINGTON
American Chemical Society
17.04.2015
Amer Chemical Soc |
Subjects | |
Online Access | Get full text |
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Summary: | A formal synthesis of the antiasthma drug montelukast sodium is described, wherein the key chiral diol intermediate was accessed with greater convergence of the C–C bond-forming steps as compared to previous routes. Improved synthetic efficiency was achieved by deploying homogeneous metal-based catalysis in two pivotal steps. In the first, a tandem Mizoroki–Heck reaction and double-bond isomerization between a previously known allyl alcohol intermediate and a hindered 2-(2-halophenyl)propan-2-ol secured direct access to the 3-(2-(2-hydroxypropan-2-yl)phenyl)-1-phenylpropan-1-one moiety in the product. In the second step, asymmetric hydrogenation of the ketone functionality in the Mizoroki–Heck reaction product provided a convenient method to introduce the benzylic alcohol chiral center and obtain the desired chiral diol precursor of montelukast sodium. A detailed catalyst screening led to the identification of ((R)-Xyl-BINAP)((R,R)-DPEN)RuCl2 as a catalyst that afforded an enantioselectivity of 99% ee in the hydrogenation step on a multigram lab scale at a molar substrate:catalyst loading of 5000:1. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-3263 1520-6904 |
DOI: | 10.1021/acs.joc.5b00197 |