Diastereoselective Diels-Alder reactions of N-sulfonyl-1-aza-1,3-butadienes with optically active enol ethers: an asymmetric variant of the 1-azadiene Diels-Alder reaction.
The first detailed study of a room-temperature asymmetric Diels-Alder reaction of N-sulfonyl-1-aza-1,3-butadienes is reported enlisting a series of 19 enol ethers bearing chiral auxiliaries, with many providing highly diastereoselective (endo and facial diastereoselection) reactions, largely the result of an exquisitely organized [4+2] cycloaddition transition state. Three new, readily accessible, and previously unexplored auxiliaries rationally emerged from the studies and provide remarkable selectivities (two of these give 49:1 endo:exo and 48:1 facial selectivity) that promise to be useful in systems beyond those detailed.
Clark
Ryan C
RC
Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA.
Pfeiffer
Steven S
SS
Boger
Dale L
DL
D001372:Aza Compounds / Q000737:chemistry*; D002070:Butadienes / Q000737:chemistry*; D004987:Ethers / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
D001372:Aza Compounds; D002070:Butadienes; D004987:Ethers