Metal sugar-vinylcarbene

Scheme 11.53 Trans-selective aldol reaction to metal sugar-vinylcarbenes.

Scheme 11.50 Sugar-vinylcarbene complexes via conjugate addition to metal alkynylcarbenes.

An extension of this strategy to sugar nucleophiles such as l,2 3,4-isopropyli-dene-a-D-galactopyranose 226 as trapping reagents affords moderate yields of or-ganometallic 0,C-disaccharides (227, 228) in which two sugar moieties are connected by a metal vinylcarbene spacer (Scheme 11.52). 

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