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. Author manuscript; available in PMC: 2013 Jan 18.
Published in final edited form as: J Am Chem Soc. 2011 Dec 16;134(2):1357–1362. doi: 10.1021/ja210655g

Table 2.

Chromene Synthesis via Carbene Complexes and Alkoxyenynes.a

graphic file with name nihms344727u2.jpg
graphic file with name nihms344727t1.jpg
23
69% (CH2Cl2)
66% (CH3CN)		 graphic file with name nihms344727t2.jpg
24
47% (CH3CN)		 graphic file with name nihms344727t3.jpg
22
88% (CH2Cl2)
65% (CH3CN)
graphic file with name nihms344727t4.jpg
25
84% (CH2Cl2)
87% (CH3CN)		 graphic file with name nihms344727t5.jpg
26
70% (CH2Cl2)		 graphic file with name nihms344727t6.jpg
27
78% (CH2Cl2)
78% (CH3CN)
graphic file with name nihms344727t7.jpg
28
74% (CH2Cl2)
86% (CH2Cl2) b
65% (CH3CN) c,d 		graphic file with name nihms344727t8.jpg
29
56% (CH2Cl2)
23% (CH3CN)		 graphic file with name nihms344727t9.jpg
30
84% (CH2Cl2)
35% (CH3CN)
graphic file with name nihms344727t10.jpg
31
41% (CH2Cl2)
83% (CH3CN) c 		graphic file with name nihms344727t11.jpg
32
61% (CH2Cl2)
48% (CH3CN) c 		graphic file with name nihms344727t12.jpg
33
45% (CH2Cl2)
26% (CH3CN)
55% (hexane)
graphic file with name nihms344727t13.jpg
34
68% (CH2Cl2)
34% (CH3CN)
74% (hexane)		 graphic file with name nihms344727t14.jpg
35
72% (CH2Cl2)
65% (CH3CN) c 		graphic file with name nihms344727t15.jpg
36
80% (CH2Cl2)
68% (CH3CN) c
a

Unless otherwise specified, all reactions were run at 0.03 M in carbene complex in the indicated solvent with 1.2 equiv of the enyne at 60 °C for 24 h. If oxidation was used it was carried out with 7.5 equiv of FeCl3•DMF complex. All yields are isolated yields after chromatography on silica gel.

b

Reaction performed with 10 equiv of aniline.

c

Oxidative workup not used.

d

Isolation after treatment of crude reaction mixture with trifluoromethane sulfonic acid.