FULL PAPERS
thankful to CSIR for his fellowship. We are thankful to
CSIR-IICT for the infrastructure and the Director, IICT for
the congenial atmosphere.
References
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Scheme 5. Scale-up synthesis of 1-bromoalkyne 2a and sol-
vent-free reaction of 1a with dry DBU.
ambient temperature. The unique characteristics of
DBU·H2O tolerated an assortment of substrates and
gave excellent yields under solvent-free conditions.
Thus the method developed in the present study
might find immense utility as a replacement for the
conventional reagents.
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General Procedure for the Synthesis of 1-Bromo-
alkynes 2
To a 5-mL screw-cap vial containing dibromoalkene 1a–z
(1 mmol) was added freshly prepared DBU·H2O (0.334 mL,
2.0 mmol, 2 equiv) dropwise over a period of 1 min against
the walls of vial at ambient temperature (25–308C). The re-
action mixture was allowed to stir at ambient temperature
for the given time. After completion of reaction (monitored
by TLC), the reaction mixture was quenched by addition of
water (10 mL) and the resulting mixture was extracted with
EtOAc/hexane (1:1, 2ꢁ10 mL); the organic layers were
washed with 5N aqueous HCl (10 mL) and water (10 mL).
The organic layers were dried over anhydrous MgSO4, the
solvent was evaporated under reduced pressure, and result-
ing residues were dried under high vacuum to afford the
corresponding analytically pure 1-bromoalkynes 2a–z.
Alternative General Procedure for Product Isolation
Upon completion of the reaction, the product was extracted
in heptane (3ꢁ10 mL) and washed with 5N HCl (5 mL).
The combined heptane layers were dried over anhydrous
MgSO4 and concentrated under reduced pressure. The re-
sulted residues were dried under high vacuum to afford the
corresponding analytically pure 1-bromoalkynes 2a–z. Hep-
tane was recovered from the concentration and reused for
the extraction of another experiment.
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Acknowledgements
V.R.D. is grateful to DST-India for the INSPIRE Faculty
award and financial support (IFA12-CH-36). S. K. M. is
Adv. Synth. Catal. 0000, 000, 0 – 0
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