10.1021/jacs.6b11937.s001
Yao Jiang
Yao
Jiang
Abdallah B. Diagne
Abdallah B.
Diagne
Regan J. Thomson
Regan J.
Thomson
Scott E. Schaus
Scott E.
Schaus
Enantioselective
Synthesis of Allenes by Catalytic
Traceless Petasis Reactions
American Chemical Society
2017
nucleophilic addition
traceless Petasis reaction
allyl boronates
alkynyl imines
enantioenriched chiral allenes
sulfinic acid
propargylic diazene
chemical properties
allenes chiral
chiral allenes
glycolaldehyde imine
reactivity patterns
enantioselective methods
enantioselective approaches
Catalytic Traceless Petasis Reactions Allenes
chiral biphenols
alkynyl boronates
Mannich product
achiral precursors
access enantioenriched allenes
allylic hydroxyl allenes
sulfonyl hydrazones
boronate addition
Enantioselective Synthesis
2017-01-25 14:18:45
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Enantioselective_Synthesis_of_Allenes_by_Catalytic_Traceless_Petasis_Reactions/4585195
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.