Stereocontrolled bond-forming reactions by conjugate additions in cyclic ehl~-unsaturated carbonyl compounds are challenging areas of current importance in organic synthesis. I Direct organocoppcr addition to furan-2(5H)-one 1 is a problematic reaction. 2 The addition of simple organocuprates, such as lithium dimethyl cuprate, requires the use of the highly toxic HMPA as cosolvent, while the reaction of other organocopper reagents, such as benzylmagnesium chloride in the presence of Cu(l) salts, proceeds in low yields. 3. In recent years, both 3-phosphorous 3b and sulfur ~ substituted furanones, though not easy available, have been shown to undergo Michael additions, allowing circumvention of these problems.
SoPh 1 2
We report a new and efficient synthesis of 3-phenylselanylfuran-2(5H)-one 2, readily available now in large amount, and its use as an efficient Michael acceptor for the ready preparation of naturally occurring 3,4disubstituted-butyrolactones, such as lignans. There is an increasing interest in developing new synthetic routes to these compounds, due to their biological properties.' To our knowledge, these substances have generally been prepared by a multi-step sequence, where the construction of the y-lactone ring is usually the last step/ 0040-402019915 -see front matter © i 999 Elsevier Science Ltd. All rights reserved. PII: S0040-4020(99)00721-8 ' " '" 3 2 4a-c <.C