319002-29-4Relevant academic research and scientific papers
Claisen rearrangements of allylic and propargylic alcohols prepared by an N-Boc-2-acyloxazolidine methodology - Application to the synthesis of original chiral building blocks
Agami, Claude,Couty, Francois,Evano, Gwilherm
, p. 29 - 38 (2002)
Stereodefined alkenols prepared in two steps from a Weinreb amide derived from (R)-phenylglycinol undergo highly stereoselective Claisen rearrangements. The masked aldehyde moiety of the produced N-Boc-alkenyloxazolidines can then be recovered and reduced without epimerization, to yield new enantiopure chiral building blocks. Alternatively, epoxidation of these N-Boc-2-alkenyloxazolidines by a well-established intramolecular bromocarbamation involving the Boc protecting group occurs stereoselectively. The resulting α,β-epoxyoxazolidines are then transformed into trisubstituted stereodefined cyclopropanes. Claisen rearrangements of propargylic alcohols, on the other hand, stereoselectively give α-allenyloxazolidines. These compounds follow a different pathway to α-alkenyloxazolidines as regards bromocarbamation. An original route to enantiopure 3-hydroxy-4-phenylpiperidine was found in the course of this study.
Claisen rearrangement of allylic alcohols prepared through N-Boc-2-acyloxazolidine methodology. Application to the synthesis of trisubstituted cyclopropanes
Agami,Couty,Evano
, p. 8301 - 8305 (2007/10/03)
Stereodefined allylic alcohols prepared from a (R)-phenylglycinol-derived Weinreb amide undergo a Claisen rearrangement with a high level of stereocontrol. The produced N-Boc-2-alcenyloxazolidines can be either hydrolyzed to afford enantiomerically enriched enals or further epoxidized using a two-step sequence. The resulting epoxyoxazolidines can then be transformed into trisubstituted cyclopropanes. (C) 2000 Elsevier Science Ltd.
