In
organic chemistry, carbonyl allylation describes methods for adding an
allyl anion to an aldehyde or ketone to produce a homoallylic alcohol.[1] The carbonyl allylation was first reported in 1876 by
Alexander Zaitsev and employed an allylzinc reagent.[2]
Enantioselective versions
In 1978, Hoffmann reported the first asymmetric carbonyl allylation using a
chiral allylmetal reagent, an
allylborane derived from
camphor.[3][4] Such methods utilize preformed allyl metal reagents. The approach is well developed using allyl boranes[5]
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As illustrated by the Keck allylation,[6] catalytic enantioselective additions of achiral allylmetal reagents to carbonyl compounds also are possible by
organostannane additions.[7]
Allylic boronate and -borane reagents have also been developed for enantioselective addition to carbonyls—in this class of reactions, the allylic boron reagent confers stereochemical control[5]
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Catalysis
In 1991,
Yamamoto disclosed the first catalytic enantioselective method for carbonyl allylation, which employed a chiral boron Lewis acid-catalyst in combination with
allyltrimethylsilane.[8] Numerous other catalytic enantioselective methods for carbonyl allylation followed.[9][6] Catalytic variants of the
Nozaki-Hiyama-Kishi reaction represent an alternative method for asymmetric carbonyl allylation, but stoichiometric metallic reductants are required.[10]
Whereas the aforementioned asymmetric carbonyl allylations rely on preformed allylmetal reagents, the
Krische allylation exploits
allyl acetate for enantioselective carbonyl allylation.[11] Selected methods for asymmetric carbonyl allylation are summarized below.
Use in total synthesis
Carbonyl allylation has been employed in the synthesis of
polyketide natural products and other oxygenated molecules with a contiguous array of stereocenters. For example, allylstannanation of a threose-derived aldehyde affords the
macrolide antascomicin B, which structurally resembles FK506 and
rapamycin, and is a potent binder of FKBP12.[12] The
Krische allylation was used to prepare the polyketide (+)-SCH 351448, a macrodiolide ionophore bearing 14 stereogenic centers.[13]
Hayashi, Tamio; Konishi, Mitsuo; Kumada, Makoto (1982-09-01). "Optically active allylsilanes. 2. High stereoselectivity in asymmetric reaction with aldehydes producing homoallylic alcohols". Journal of the American Chemical Society. 104 (18): 4963–4965.
doi:
10.1021/ja00382a046.
Roush, William R.; Walts, Alan E.; Hoong, Lee K. (1985-12-01). "Diastereo- and enantioselective aldehyde addition reactions of 2-allyl-1,3,2-dioxaborolane-4,5-dicarboxylic esters, a useful class of tartrate ester modified allylboronates". Journal of the American Chemical Society. 107 (26): 8186–8190.
doi:
10.1021/ja00312a062.
^Yus, Miguel; González-Gómez, José C.; Foubelo, Francisco (2011). "Catalytic Enantioselective Allylation of Carbonyl Compounds and Imines". Chemical Reviews. 111 (12): 7774–7854.
doi:
10.1021/cr1004474.
PMID21923136.
^Herold, Thomas; Hoffmann, Reinhard W. (1978-10-01). "Enantioselective Synthesis of Homoallyl Alcohols via Chiral Allylboronic Esters". Angewandte Chemie International Edition in English. 17 (10): 768–769.
doi:
10.1002/anie.197807682.
^Hoffmann, Reinhard W.; Herold, Thomas (1981-01-01). "Stereoselektive Synthese von Alkoholen, VII1) Optisch aktive Homoallylalkohole durch Addition chiraler Boronsäureester an Aldehyde". Chemische Berichte. 114 (1): 375–383.
doi:
10.1002/cber.19811140139.
^
abDenmark, S. E.; Almstead, N. G. In Modern Carbonyl Chemistry; Otera, J., Ed.; Wiley-VCH: Weinheim, 2000; Chapter 10.
^
abKeck, Gary E.; Tarbet, Kenneth H.; Geraci, Leo S. (1993-09-01). "Catalytic asymmetric allylation of aldehydes". Journal of the American Chemical Society. 115 (18): 8467–8468.
doi:
10.1021/ja00071a074.
^Costa, Anna Luisa; Piazza, Maria Giulia; Tagliavini, Emilio; Trombini, Claudio; Umani-Ronchi, Achille (1993-07-01). "Catalytic asymmetric synthesis of homoallylic alcohols". Journal of the American Chemical Society. 115 (15): 7001–7002.
doi:
10.1021/ja00068a079.
^Hargaden, Gráinne C.; Guiry, Patrick J. (2007-11-05). "The Development of the Asymmetric Nozaki–Hiyama–Kishi Reaction". Advanced Synthesis & Catalysis. 349 (16): 2407–2424.
doi:
10.1002/adsc.200700324.
^Brittain, Dominic E. A.; Griffiths-Jones, Charlotte M.; Linder, Michael R.; Smith, Martin D.; McCusker, Catherine; Barlow, Jaqueline S.; Akiyama, Ryo; Yasuda, Kosuke; Ley, Steven V. (2005).
"Total Synthesis of Antascomicin B". Angewandte Chemie International Edition. 44 (18): 2732–2737.
doi:
10.1002/anie.200500174.
ISSN1521-3773.
PMID15806607.