Indium-Promoted Allylation of Alkynes with Allylic Alcohols: Highly Regioselective Synthesis of Halogen-Substituted 1,4-Dienes

Abstract

Indium-promoted allylation of alkynes by direct use of allyl alcohols as the allylating agents has been developed under mild conditions, in which a wide range of allylic alcohols and alkynes (both aromatic and aliphatic alkynes) could be tolerated, and the corresponding halogen-substituted 1,4-dienes were obtained in moderate to excellent yields.

GRAPHICAL ABSTRACT

Keywords:

• Alkynes
• allyl alcohols
• allylation
• halogen-substituted 1,4-dienes
• indium(III) salt

ACKNOWLEDGMENT

We are grateful for the financial support from the National Science Foundation of China (20802072).

Notes

^a Reaction conditions: cyclohex-2-enol 1a (0.25 mmol), phenylacetylene 2a (0.38 mmol), MX_n (0.06–0.25 mmol).

^b Isolated yields based on alcohol 1a.

^c The reaction was carried out at 60 °C.

^a Reaction conditions: allylic alcohols 1 (0.25 mmol), alkynes 2 (0.38 mmol), InX₃ (0.125 mmol), BrCH₂CH₂Br (1 mL), room temperature.

^b Isolated yields based on allylic alcohols 1..

^c The ratio of E/Z is determined by ¹ H NMR analysis on the crude mixture.

^d The reaction was carried out in the presence of InCl₃ at 60 °C.