COMMUNICATIONS
Silica Gel-Mediated Hydroamination/Semipinacol Rearrangement
References
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Experimental Section
General Procedure
To a stirred solution of in situ formed LDA (3.5 equiv.) in
THF (3 mL) at À788C was added the appropriate alkyne
(1.75 mmol). The resulting reaction mixture was allowed to
stir for a further 1 h before the ketone 1 (0.5 mmol) in THF
(2 mL) was added to the reaction mixture and stirred for 1 h
at the same temperature and at room temperature for 1 h.
Upon completion, the reaction mixture was quenched with
saturated NH4Cl (15 mL) and extracted with EtOAc (2ꢁ
15 mL). The combined organic layers were washed with
brine (20 mL), dried over MgSO4 and concentrated under
reduced pressure. The crude mixture obtained was dissolved
with n-hexane/EtOAc (10 mL, 20:1 v/v) contained in an
open round-bottom flask and silica gel (3 g) was added. The
reaction mixture was stirred and monitored by TLC analysis
until completion. The reaction mixture was filtered, washed
with EtOAc (20 mL), concentrated under reduced pressure
and purified by flash column chromatography on silica gel
(eluent: n-hexane/EtOAc=10:1) to give the product 3.
Acknowledgements
This work is supported by a College of Science Start-Up
Grant from Nanyang Technological University and an
A*STAR-MSHE Joint Grant (122 070 3062) from A*STAR,
Singapore. We thank Drs. Yongxin Li and Rakesh Ganguly
of this Division for providing the X-ray crystallographic data
reported in this work.
Adv. Synth. Catal. 2014, 356, 353 – 358
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
357