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. Author manuscript; available in PMC: 2010 Jul 2.
Published in final edited form as: Tetrahedron. 2009 Jun 27;65(26):4957–4967. doi: 10.1016/j.tet.2009.03.103

Table 2.

NHC-catalyzed cyclization-lactonization of substrate 13.

graphic file with name nihms123358f14.jpg
Entry Catalyst (mol%) Base (mol%) Solvent (conc.) Temp. (°C) A : B : Ca
1 RMesCl (15%) DBU(10%) tBuOH (0.1M) 60 3 : 1 : 2
2 IMesCl (15%) DBU(10%) tBuOH (0.1M) 60 1 : 1.5 : 8
3 12 (15%) DBU(10%) tBuOH (0.1M) 60 4 : 1 : 1
4 RMesCl (15%) DBU(10%) 10:1 THF:tBuOH (0.10 M) 60 1 : 1.5 : -
5 RMesCl (15%) DBU(10%) 10:1 THF:tBuOH (0.10 M) 40 1 : 1.3 : -
6 RMesCl (15%) DIPEA(10%) 10:1 THF:tBuOH (0.10 M) 40 1 : 1.2 : -
7 RMesCl (15%) tBuOK(10%) 10:1 THF:tBuOH (0.10 M) 40 1 : 1 : 1
8 RMesCl (15%) DBU(10%) 10:1 THF:tBuOH (0.10 M) 20 1 : - : 6.7
9 RMesCl (15%) DBU(10%) 10:1 THF:tBuOH (0.05 M) 40 4 : 1 : 1
10 RMesCl (15%) DIPEA(10%) 10:1 THF:tBuOH (0.05 M) 40 1 : 1 : trace
11 RMesCl (15%) DBU (50%) 10:1 THF:tBuOH (0.05 M) 40 1 : - : 10
12 RMesCl (15%) DIPEA (50%) 10:1 THF:tBuOH (0.05 M) 40 1 : 1 : -
13 RMesCl (15%) DBU (10%) 10:1 THF:tBuOH (0.01 M) 40 3 : 1 : trace

All reactions listed proceeded with 100% conversion; isolated yields were not determined.

a

Product pathway ratios determined from 1H NMR analysis of umpurified reaction mixtures.