- Diastereoselective [4 + 1] Cycloaddition of Alkenyl Propargyl Acetates with CO Catalyzed by [RhCl(CO)2]2
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A class of alkenyl propargyl acetates, RCH(OAc)C≡CC(CH 3)=CH2 (5), are found to undergo [4 + 1] cycloaddition with CO (1 atm) in the presence of [RhCl(CO)2]2 in refluxing 1,2-dichloroethane to give cyclopentenones (6) in good yields. It has been demonstrated that, when the R group of 5 is a phenyl group bearing o-electron-withdrawing substituents, up to 10:1 diastereoselectivity and 96% yield can be achieved for the [4 + 1] cycloaddition. This process provides a convenient method to construct highly functionalized cyclopentenones that are useful in organic synthesis.
- Chen, Wei,Tay, Jia-Hui,Yu, Xiao-Qi,Pu, Lin
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experimental part
p. 6215 - 6222
(2012/09/21)
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- Organoboranes. 38. A Facile and Highly Efficient Addition of B-1-Alkynyl-9-borabicyclononanes to Aldehydes and Ketones: An Exceptionally Chemoselective Synthesis of Propargylic Alcohols
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B-1-Alkynyl-9-borabicyclononanes (B-1-alkynyl-9-BBN) readily undergo addition to aldehydes and ketones and afford the propargylic alcohols in very high isolated yields.Unlike many other alkynyl metals (RCCM, M = Li, Na, K, Mg, Zn, and Al), which
- Brown, Herbert C.,Molander, Gary A.,Singh, Shankar M.,Racherla, Uday S.
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p. 1577 - 1582
(2007/10/02)
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