TY - JOUR
T1 - Enantioselective synthesis of allenes by catalytic traceless petasis reactions
AU - Jiang, Yao
AU - Diagne, Abdallah B.
AU - Thomson, Regan J.
AU - Schaus, Scott E.
N1 - Funding Information:
S.E.S. and Y.J. gratefully acknowledge the NIH for research support (R01 GM078240) and instrumentation (P50 GM067041). R.J.T. and A.B.D. gratefully acknowledge the NSF for research support (CHE1361173) and the ARCS Foundation for the Daniel D. and Ada L. Rice Foundation Scholarship to A.B.D.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/2/8
Y1 - 2017/2/8
N2 - Allenes are useful functional groups in synthesis as a result of their inherent chemical properties and established reactivity patterns. One property of chemical bonding renders 1,3-substituted allenes chiral, making them attractive targets for asymmetric synthesis. While there are many enantioselective methods to synthesize chiral allenes from chiral starting materials, fewer methods exist to directly synthesize enantioenriched chiral allenes from achiral precursors. We report here an asymmetric boronate addition to sulfonyl hydrazones catalyzed by chiral biphenols to access enantioenriched allenes in a traceless Petasis reaction. The resulting Mannich product from nucleophilic addition eliminates sulfinic acid, yielding a propargylic diazene that performs an alkyne walk to afford the allene. Two enantioselective approaches have been developed; alkynyl boronates add to glycolaldehyde imine to afford allylic hydroxyl allenes, and allyl boronates add to alkynyl imines to form 1,3-alkenyl allenes. In both cases, the products are obtained in high yields and enantioselectivities.
AB - Allenes are useful functional groups in synthesis as a result of their inherent chemical properties and established reactivity patterns. One property of chemical bonding renders 1,3-substituted allenes chiral, making them attractive targets for asymmetric synthesis. While there are many enantioselective methods to synthesize chiral allenes from chiral starting materials, fewer methods exist to directly synthesize enantioenriched chiral allenes from achiral precursors. We report here an asymmetric boronate addition to sulfonyl hydrazones catalyzed by chiral biphenols to access enantioenriched allenes in a traceless Petasis reaction. The resulting Mannich product from nucleophilic addition eliminates sulfinic acid, yielding a propargylic diazene that performs an alkyne walk to afford the allene. Two enantioselective approaches have been developed; alkynyl boronates add to glycolaldehyde imine to afford allylic hydroxyl allenes, and allyl boronates add to alkynyl imines to form 1,3-alkenyl allenes. In both cases, the products are obtained in high yields and enantioselectivities.
UR - http://www.scopus.com/inward/record.url?scp=85011955153&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85011955153&partnerID=8YFLogxK
U2 - 10.1021/jacs.6b11937
DO - 10.1021/jacs.6b11937
M3 - Article
C2 - 28121128
AN - SCOPUS:85011955153
SN - 0002-7863
VL - 139
SP - 1998
EP - 2005
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 5
ER -