Oxazolidinones are powerful promoters of the Nazarov reaction, enabling the cyclization of conventionally resistant substrates to be achieved under mild conditions. They exert excellent regio- and torquoselective control in both the conventional Nazarov reaction giving cyclopentenones and in the "interrupted" Nazarov reaction, giving more highly substituted multistereocenter containing products.

An efficient, formal enantioselective synthesis of (+)- and (-)-pauciflorol F has been achieved using a recently introduced oxazolidinone controlled torquoselective Nazarov reaction. The absolute stereochemistry of pauciflorol F and its biosynthetic precursors has been unambiguously confirmed using X-ray crystallography.

Oxazolidinone-Promoted, Torquoselective Nazarov Cyclizations. -In the presence of an excess of MesOH or TfOH, divinyl and aryl vinyl ketones bearing an oxazolidinone auxiliary undergo efficient and highly stereoselective cyclization to optically active cyclopentenone derivatives. In the case of ketone (IX), tandem ring closure takes place giving the fused cyclopentanone (X). The auxiliary can be removed with lithium naphthalide or SmI 2 . -(KERR, D. J.; MILETIC, M.; CHAPLIN, J. H.; WHITE, J. M.; FLYNN*, B. L.; Org. Lett. 14 (2012) 7, 1732-1735, http://dx.doi.org/10.1021/ol300316a ; Med. Chem. Drug Action, Monash Inst. Pharm. Sci., Monash Univ., Parkville, Victoria 3052, Australia; Eng.) -Jannicke 31-055