The first systematic study of catalytic enantioselective 1,2-additions to acrolein is described. Specifically, using allyl alcohol as a tractable, inexpensive acrolein proelectrophile, iridiumcatalyzed acrolein allylation is achieved with high levels of regio-, anti-diastereo-, and enantioselectivity. This process delivers 3hydroxy-1,5-hexadienes, a useful compound class that is otherwise challenging to access via enantioselective catalysis. Two-fold use of this method unlocks concise total syntheses of amphidinolide R (9 vs 23 steps, LLS) and amphidinolide J (9 vs 23 or 26 steps, LLS), which are prepared in fewer than half the steps previously possible, and the first total synthesis of amphidinolide S (10 steps, LLS).
The first metal-catalyzed oxidative alkynylations of primary alcohols or aldehydes to form α,βacetylenic ketones (ynones) are described. Deuterium labelling studies corroborate a novel reaction mechanism in which alkyne hydroruthenation forms a transient vinylruthenium complex that deprotonates the terminal alkyne to form the active alkynylruthenium nucleophile.
Intermolecular metal-catalyzed C−C couplings of unactivated primary alcohols or aldehydes to form ketones are catalogued. Reactions are classified on the basis of pronucleophile. Protocols involving premetalated reagents or reactants that incorporate directing groups are not covered. These methods represent an emerging alternative to classical multistep protocols for ketone construction that exploit premetalated reagents and/or steps devoted to redox manipulations and carboxylic acid derivatization.
O-Acetyl 1,3-propanediol serves as an
acrolein
proelectrophile in π-allyliridium-C,O-benzoate-catalyzed carbonyl allylations mediated by racemic
α-substituted allylic acetates. Using the iridium catalyst modified
by (R)-SEGPHOS, a variety of 3-hydroxy-1,5-hexadienes
are formed with uniformly high levels of regio-, anti-diastereo-, and enantioselectivity.
The first metal‐catalyzed oxidative alkynylations of primary alcohols or aldehydes to form α,β‐acetylenic ketones (ynones) are described. Deuterium labelling studies corroborate a novel reaction mechanism in which alkyne hydroruthenation forms a transient vinylruthenium complex that deprotonates the terminal alkyne to form the active alkynylruthenium nucleophile.
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