Super silyl

Siloxy-a-haloketones have been prepared with high anti-selectivity via a Mukaiyama aldol of super-silyl enol ethers, using the tris(trimethylsilyl)silyl (or TTMSS) group. Most cases involve chlorine, but fluorine works too, and one-pot sequential double-aldol versions deliver, 5-bis(super-silyl)oxy-a,y-dihaloketones with 0 control of four contiguous chiral centres. [Pg.26]

Boxer MB, Yamamoto H (2007) Super Silyl group for diastereoselective sequential reactions access to complex chiral architecture in one pot J Am Chem Soc 129 2762-2763... [Pg.334]

Boxer M, Yamamoto H (2008) Ketone super silyl enol ethers in sequential reactions diastereoselective generation of tertiary carbinols in one pot. J Am Chem Soc 130 1580-1582... [Pg.334]

Products 4 and 9 have adjacent stereogenic centers. Hisashi Yamamoto of the University of Chicago has introduced J. Am. Chem. Soc. 2007,129,2762) the linchpin reagent acetaldehyde super silyl enol ether 11. Diastereoselective addition of 11 to the enantiomerically-pure aldehyde 10, with concomitant silyl transfer, followed by the addition of allyl magnesium bromide delivered the protected triol 12 in high de and ee. [Pg.78]

SCHEME 2.122 Aldol reactions using Yamamoto s super silyl concept. [Pg.102]

Both aldehyde- and ketone-derived super silyl enol ethers were shown to succeed in this system (Table 4.5). The reaction proceeded smoothly in aU cases at —40 °C with a 3 mol% catalyst loading. Silyl enol ether 15e led to gem-dimethylcyclobutane 16g, with excellent stereoselectivity... [Pg.119]

Recently, Boxer and Yamamoto have developed the aldol reaction using super-silyl (tris(trimethylsilyl)silyl-, (TMS)3Si-) ether (Scheme 8.27). " The super-sUyl features the transfer to a hydroxy group, which makes it possible to... [Pg.227]

SCHEME 8.27. The sequential aldol reaction and nucleophihc addition using super-silyl ethers. [Pg.228]

SCHEME 8.28. The triple-aldol cascade reaction using super-silyl ethers. [Pg.229]

Boxer MB, Albert BJ, Yamamoto H (2009) The super silyl group in diastereoselective aldol and cascade reactions. Aldrichimica Acta 42 3... [Pg.207]

Boxer MB, Yamamoto H (2008) Super silyl group for a sequential diastereoselective aldol—polyhalomethyllithium addition reaction. Org Lett 10 453... [Pg.219]

Yamaoka Y, Yamamoto H (2010) Super silyl stereo-directing groups for complete 1,5-syn and -anti stereoselectivities in the aldol reactions of p-siloxy methyl ketones with aldehydes. J Am Chem Soc 132 5354... [Pg.219]

Brady PB, Yamamoto H (2012) Rapid and stereochemically flexible synthesis of polypropionates super-silyl-govemed aldol cascades. Angew Chem Int Ed 51 1942... [Pg.219]

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