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Enantioselective synthesis of kedarcidin chromophore aglycon

Record Type:	Electronic resources : Monograph/item
Title/Author:	Enantioselective synthesis of kedarcidin chromophore aglycon
Author:	Hogan, Philip C.
Description:	303 p.
Notes:	Adviser: Andrew G. Myers.
Notes:	Source: Dissertation Abstracts International, Volume: 65-05, Section: B, page: 2419.
Contained By:	Dissertation Abstracts International65-05B.
Subject:	Chemistry, Organic.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3131868
ISBN:	0496791087

Enantioselective synthesis of kedarcidin chromophore aglycon
Hogan, Philip C.

Enantioselective synthesis of kedarcidin chromophore aglycon [electronic resource] - 303 p.

Adviser: Andrew G. Myers.

Thesis (Ph.D.)--Harvard University, 2004.

*Please refer to dissertation for diagrams.

ISBN: 0496791087Subjects--Topical Terms:

193634
Chemistry, Organic.

Enantioselective synthesis of kedarcidin chromophore aglycon
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245 1 0 $a Enantioselective synthesis of kedarcidin chromophore aglycon $h [electronic resource]
300 $a 303 p.
500 $a Adviser: Andrew G. Myers.
500 $a Source: Dissertation Abstracts International, Volume: 65-05, Section: B, page: 2419.
502 $a Thesis (Ph.D.)--Harvard University, 2004.
520 # $a *Please refer to dissertation for diagrams.
520 # $a An enantioselective synthesis of kedarcidin chromophore aglycon in differentially protected form (26) is described. The route is 25 steps in the longest linear sequence, with an average yield of 82% per step (overall yield 1%).*
520 # $a Several of the intermediates in this route (e.g., 51 and 59) as well as the protected aglycon (26) exhibited conformational isomerism on the NMR time scale, attributed to hindered rotation of the chloropyridine ring (atropisomerism). The kinetics and thermodynamics of these processes were studied in detail. Kedarcidin chromophore aglycon ( 26) was observed to undergo cycloaromatization rapidly at ambient temperature in the presence of good hydrogen-atom donors, providing the epoxide 60 as a single atropisomer. These results suggest that atropisomeric forms of kedarcidin chromophore (1) are interconvertible at ambient temperature, and that 1 is capable of cycloaromatization at ambient temperature without chemical activation.
520 # $a The key step in the sequence was the transannular cyclization of the bromoenetriyne 28, induced by lithium-halogen exchange, affording the ansa-bridged bicyclo[7.3.0]dodecadienediyne 56. Silyl ether cleavage followed by hydroxyl-directed epoxidation and hydroxyl protection transformed 56 into the epoxide 59. Completion of the synthesis of 26 was achieved by dehydration of 59 in the presence of Martin sulfurane.*
590 $a School code: 0084.
650 # 0 $a Chemistry, Organic. $3 193634
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710 0 # $a Harvard University. $3 212445
773 0 # $g 65-05B. $t Dissertation Abstracts International
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790 1 0 $a Myers, Andrew G., $e advisor
791 $a Ph.D.
792 $a 2004
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