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. Author manuscript; available in PMC: 2010 Feb 5.
Published in final edited form as: Org Lett. 2009 Feb 5;11(3):567–570. doi: 10.1021/ol802343z

Table 2.

Effects of leaving group on yield of 3β-azido-cholest-5-ene (3)

entry substrate Lewis acid reaction
conditions		 yield
(%)
1 graphic file with name nihms86707t9.jpg BF3•OEt2
(5 equiv)		 22 °C, 3 h 92
2 graphic file with name nihms86707t10.jpg SnCl4
(1 equiv)		 −20 °C, 1 h
to 22 °C, 2
h		 50 (3);
45 (4)
3 graphic file with name nihms86707t11.jpg BF3•OEt2
(2 equiv)		 22 °C, 2 h trace
4 graphic file with name nihms86707t12.jpg BF3•OEt2
(2 equiv)		 22 °C, 2 h NR
5 graphic file with name nihms86707t13.jpg BF3•OEt2
(2 equiv)		 22 °C, 2 h NR

Reactions were run on a 1 mmol scale in anhydrous CH2Cl2 containing TMSN3 (1.1 equiv). Recovery of starting material (4)is additionally shown in entry 2. NR: no reaction observed.