A Catalytic Asymmetric Chlorocyclization of Unsaturated Amides
作者:Arvind Jaganathan、Atefeh Garzan、Daniel C. Whitehead、Richard J. Staples、Babak Borhan
DOI:10.1002/anie.201006910
日期:2011.3.7
The asymmetricchlorocyclization of unsaturatedamides catalyzed by (DHQD)2PHAL yields oxazoline and dihydrooxazine derivatives (see scheme). The reaction is operationally simple and employs 1–2 mol % of the commercially available (DHQD)2PHAL (hydroquinidine 1,4‐phthalazinediyl diether) catalyst. Different substitution patterns of the olefin as well as aromatic and aliphatic olefin substituents are
A highly enantioselective bromocyclization of allylic amides with N-bromosuccinimide (NBS) was developed with DTBM-BINAP as a catalyst, affording chiral oxazolines with a tetrasubstituted carbon center in high yield with up to 99% ee. By utilizing the bromo substituent as a handle, the obtained compounds were converted to synthetically useful chiral building blocks.