Practical synthesis of functionalized terminal alkynes, 3,3,3-triethoxypropyne and ketal protected prop-2-ynones

ABSTRACT

Practical and economical synthesis of synthetically valuable 3,3,3-triethoxypropyne, ketal protected phenyl and methyl substituents prop-2-ynones is described. Bromination and subsequent 18-crown-6 catalyzed elimination of triethylorthoacrylate and ketal protected terminal alkenes with methyl and phenyl substituent which are inturn readily available from triethylorthopropionate, 3-chlorobutan-2-one and propiophenone afforded multigram quantities (>10 g) of corresponding functionalized terminal alkynes. Exploration of the synthetic utility of these alkynes is also demonstrated by the acetylenic substitution of the phenylalaninol derived 1,2-cyclic sulfamidate to deliver chiral alkynylated amines.

GRAPHICAL ABSTRACT

KEYWORDS:

• 1,2-Cyclic sulfamidates
• ketal
• orthoester
• terminal alkynes

Additional information

Funding

The authors gratefully acknowledge Manisa Celal Bayar University for financial support through a project (FEF-2011-030).