Rearrangement asymmetric Carroll

The Carroll rearrangement proceeds via a highly ordered chair-like transition state and therefore allows for a high degree of diastereoselectivity and asymmetric induction [33]. Recently, Enders and coworkers have developed an asymmetric dia- 

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D. Enders and co-workers have achieved the enantioselective total synthesis of antibiotic (-)-malyngolide by using the asymmetric Carroll rearrangement as the key step. ... 

Enders, D., Knopp, M., Runsink, J., Raabe, G. Diastereo- and enantioselective synthesis of polyfunctional ketones with adjacent quaternary and tertiary centers by asymmetric Carroll rearrangement. Angew. Chem., Int. Ed. Engl. 1995, 34, 2278-2280. 

Claisen and Carroll rearrangements of hydroxyalkenylsilanes provide an asymmetric synthesis of allylsilanes from optically active secondary alcohols39,40. 

Asymmetric decarboxylative rearrangement (Carroll rearrangement) of allyl a-acetamido-/3-ketocarboxylates, catalysed by a palladium complex modified with a chiral phosphine ligand, has been reported to give optically active /,5-unsaturated a-amino ketones with up to 90% ee (Scheme 92).135 The mechanism for the Carroll rearrangement is shown in Scheme 93. 

Table 8.3 Lewis acid-assisted asymmetric (SAMP/RAMP) y -hydrazono allylic ester Carroll rearrangements.

Enders Carroll rearrangement methodology was applied to the asymmetric synthesis of (-)-malyngolide 120 (Scheme 8.41) [36]. 

The asymmetric construction of quaternary centers starting from /3-keto allyl esters, e.g., reaction of 24 to give 25, is possible using a Pd(0)-mediated Carrol rearrangement. A napthyl version of Trost ligand was the best chiral ligand for this process (eq 18). 

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