A direct preparation of silyl oxazoles: a dramatic chemoselectivity difference between R3SiOTf and R3SiCl
作者:Ross A. Miller、Randi M. Smith、Sandor Karady、Robert A. Reamer
DOI:10.1016/s0040-4039(01)02342-5
日期:2002.2
General. highly selective silylation conditions for the ambident oxazole anion (isocyano enolate) have been found. The chemoselectivity between O-silylation and C-silylation changed from <1:99 to >99:1 upon switching from R3SiCl to R3SiOTf. (C) 2002 Elsevier Science Ltd. All rights reserved.
Oxazole Synthesis by Sequential Asmic-Ester Condensations and Sulfanyl–Lithium Exchange–Trapping
作者:Louis G. Mueller、Allen Chao、Embarek Alwedi、Maanasa Natrajan、Fraser F. Fleming
DOI:10.1021/acs.orglett.1c00288
日期:2021.2.19
Oxazoles are rapidly assembled through a sequential deprotonation–condensation of Asmic, anisylsulfanylmethylisocyanide, with esters followed by sulfanyl–lithium exchange–trapping. Deprotonating Asmic affords a metalated isocyanide that efficiently traps esters to afford oxazoles bearing a versatile C-4 anisylsulfanyl substituent. Interchange of the anisylsulfanyl substituent is readily achieved through
A Convenient Oxazole C-2 Protecting Group: The Synthesis of 4- and 5-Substituted Oxazoles via Metalation of 2-Triisopropylsilyloxazoles
作者:Ross A. Miller、Randi M. Smith、Benjamin Marcune
DOI:10.1021/jo051490m
日期:2005.10.1
Metalation of oxazoles at the 4 and 5 position was achieved after regioselective C-2 silyl protection. Removal of the protecting group was then accomplished under mild conditions allowing for a straightforward preparation of C-5 monosubstituted and C-4,5 disubstituted oxazoles. The first practical C-2 protecting group of oxazoles has been demonstrated.