In:
Advanced Synthesis & Catalysis, Wiley, Vol. 358, No. 18 ( 2016-09-15), p. 2912-2922
Abstract:
N‐Protected β‐propargylamino acrylic esters with a push‐pull olefinic bond afforded good to high yields of dihydropyridines upon treatment with 5% tris(2‐furyl)phosphine‐gold(I) chloride/silver(I) tetrafluoroborate [(TFP)AuCl/AgBF 4 ] in anhydrous benzene. Carbamate and sulfonyl groups were employed for nitrogen protection. On a model enyne, the p ‐methoxybenzenesulfonyl (MBS) group was found to be a better protective group than tosyl in terms of cyclization yield, and also the yield of elimination to the corresponding 2,3,4‐trisubstituted pyridines. Boc‐protected dihydropyridines underwent partial deprotection/oxidation under the cyclization conditions, which enabled a more straightforward, one‐pot preparation of the corresponding pyridines. In another application, an appropriately substituted derivative protected as a stable methoxycarbamate was subjected to catalytic hydrogenation affording the known precursor of paroxetine. The chemoselectivity of enyne cyclization (dihydropyridine vs . pyrrole) is governed, among other factors, by C‐3 substitution. Dihydropyridines were obtained as sole products regardless of the catalyst/conditions when C‐3 was unsubstituted. magnified image
Type of Medium:
Online Resource
ISSN:
1615-4150
,
1615-4169
DOI:
10.1002/adsc.v358.18
DOI:
10.1002/adsc.201600412
Language:
English
Publisher:
Wiley
Publication Date:
2016
detail.hit.zdb_id:
2041384-1
detail.hit.zdb_id:
2033084-4
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