Diastereoselective Synthesis of Chiral 3-Aryl-1-alkynes from Bromoallenes

Significance

Optically active 1-alkynes can be useful intermediates in the synthesis of a variety of chiral compounds. This method offers a simple route to these compounds from chiral bromo­allenes, based on highly 1,3-anti-stereoselective copper-catalyzed substitution reactions. Good chirality transfer is observed in this process and the stereoselectivity usually exceeds 90%, although for some substrates the extensive formation of allenes may take place. Arylmagnesium or arylzinc halides as well as alkylzinc halides were used successfully in this substitution reaction. Examples of the transformation of the resulting acetylenes into other chiral molecules are also given.