Organic Chemistry Portal
Organic Chemistry Highlights

Monday, February 28, 2011
Douglass F. Taber
University of Delaware

New Methods for C-C Bond Construction: The Burke Synthesis of (-)-Peridinin

Hideki Yorimitsu and Koichiro Oshima of Kyoto University observed (J. Am. Chem. Soc. 2010, 132, 8878. DOI: 10.1021/ja102303s) that Rh-catalyzed addition of 2 to a terminal allene 1 generated an allylic organometallic, that coupled with electrophiles to give the branched product 3. Regan J. Thomson of Northwestern University devised (Nature Chemistry 2010, 2, 294. DOI: 10.1038/nchem.576) the reagent 5, that added to an aldehyde 4 to give the reduced allylically-coupled product 6. Nuno Maulide of the Max-Planck-Institut, Mülheim noted (Angew. Chem. Int. Ed. 2010, 49, 1583. DOI: 10.1002/anie.200906416) the remarkable rearrangement of 7 to 8. Jon A. Tunge of the University of Kansas showed (Org. Lett. 2010, 12, 740. DOI: 10.1021/ol902828p) that nitronate allylation could be effected by the Pd-mediated decarboxylation of 9.

Takashi Tomioka of the University of Mississippi developed (Org. Lett. 2010, 12, 2171. DOI: 10.1021/ol100534s) a convenient reagent for the conversion of an aldehyde 11 to the Z-unsaturated nitrile 12. Xiaodong Shi of the University of West Virginia established (Org. Lett. 2010, 12, 2088. DOI: 10.1021/ol100576m) that Au-mediated rearrangement of 13 led to the Z-iodo enone 14. T. V. RajanBabu of Ohio State University developed (Org. Lett. 2010, 12, 2622. DOI: 10.1021/ol100824f) a Pd catalyst for the selective double functionalization of a terminal alkyne 15 to the stannane 16. The subsequent tandem Stille and Suzuki couplings proceeded efficiently.

The controlled construction of tetrasubstituted alkenes is particularly challenging. Kohei Endo and Takanori Shibata of Waseda University put forward (J. Org. Chem. 2010, 75, 3469. DOI: 10.1021/jo1003407) what promises to be a general solution to this problem, the addition of the bis-boronate 17 to a ketone 18.

Alkynes are usually prepared by direct alkylation. Gérard Cahiez of the Université de Paris 13 established (Angew. Chem. Int. Ed. 2010, 49, 1278. DOI: 10.1002/anie.200905816) an alternative, the coupling of a Grignard reagent with a 1-bromoalkyne 20. Gregory B. Dudley of Florida State University developed (J. Org. Chem. 2010, 75, 3260. DOI: 10.1021/jo100249g) a complementary route to internal alkynes, based on the fragmentation of 22.

Enantiomerically-pure allenes are ubiquitous components of physiologically-active natural products. Weiping Tang of the University of Wisconsin optimized (J. Am. Chem. Soc. 2010, 132, 3664. DOI: 10.1021/ja100173w) the bromolactonization of a Z enyne 24 to give the allene 25. André Charette of the Université de Montreal prepared (Org. Lett. 2010, 12, 564. DOI: 10.1021/ol902766f) the allene 27 by the opening of the alkyne 26. Martin D. Burke of the University of Illinois employed (J. Am. Chem. Soc. 2010, 132, 6941. DOI: 10.1021/ja102721p) a building block strategy for the assembly of (-)-Peridinin 30, the penultimate step of which was the coupling of 28 with the enantiomerically-pure allene 29.

D. F. Taber, Org. Chem. Highlights 2011, February 28.