PAPER	Synthesis 2006: 3801-3804   DOI: 10.1055/s-2006-950298
© Georg Thieme Verlag Stuttgart · New York
Chemoselective Thioacetalization Using 3-(1,3-Dithian-2-ylidene)pentane-2,4-dione as an Odorless and Efficient Propane-1,3-dithiol Equivalent under Solvent-Free Conditions
Yan Ouyang, Dewen Dong*, Chunbai Zheng, Haifeng Yu, Qun Liu*, Zhenqian Fu
Department of Chemistry, Northeast Normal University, Changchun, 130024, P. R. of China Fax: +86(431)5098635; e-Mail: dongdw663@nenu.edu.cn;
Received 10 May 2006

Abstract

As a non-thiolic, odorless propane-1,3-dithiol equivalent, 3-(1,3-dithian-2-ylidene)pentane-2,4-dione has been investigated in acid-promoted thioacetalization under solvent-free conditions. A range of selected aldehydes and aliphatic ketones have been converted into the corresponding dithioacetals in high yields. The relatively slow reaction rate of aromatic ketones allowed chemoselective protection of aromatic aldehydes or aliphatic ketones, in contrast to aromatic ketones.

Key words

chemoselectivity - concentrated hydrochloric acid - solvent-free reaction - thioacetalization - α-oxo ketene S,S-acetals