A new method for the conversion of aldehydes (RCH2CHO)to acetylenes (RC&.tbnd;CH) via 1-alkenylstannanes. Application to the synthesis of 9(O)-thia-Δ6-PGI1
✍ Scribed by Masakatsu Shibasaki; Yasuhiro Torisawa; Shiro Ikegami
- Book ID
- 104219675
- Publisher
- Elsevier Science
- Year
- 1982
- Tongue
- French
- Weight
- 232 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
A method for the conversion of aldehydes to acetylenes via I-alkenylstannanes is reported, including its application to the synthesis of 9(O)-thia-A6-PCIl.
In connection with studies directed toward the synthesis of prostacyclin analogs, it was required to develop a mild method for the transformation of aldehydes (RCH CHO) 2 to acetylenes (RC&H),l hopefully via 1-alkenylstannanes.
In this communication, we wish to report a solution to this problem as well as its successful application to the synthesis of 9(O)-thia-Ah-PGI1 (26).
Previously we have reported a general method for the preparation of a-haloalkylstannanes from aldehydes. 2 Therefore, if the dehydrohalogenation of a-haloalkylstannanes occurs readily to lead to 1-alkenylstannanes, it occurred to us that a series of reactions (RCH2CH0 -----t RCH2CH(X)Sn(n-Bu)3---tRCH=CHSn(n-Bu)3+RCrCH) would offer a solution to this problem. 3 In the first place, our assumption was tested using the simple model compound (1). The aldehyde (l_)
was converted to the quite stable cl-bromoalkylstannane (2)4 by the method reported by us2 in 80% overall yield from 1. Treatment of z with 3 equiv of DBU in toluene at 110°C for 2 hr was