Asymmetric CBS reduction

To achieve synthesis of (-)-arisugacin A [1], (7 J-89 was obtained readily from 2-methyl-l,3-cyclohexanedione 88 in 4 steps with an overall yield of 46%, featuring vinylogous ester formation, Stork-Danheiser double alpha methylation,52,68,69 vinyl Grignard addition followed by acidic work-up,68 and an asymmetric CBS reduction [Scheme 21].70,71... 

Preparation. [(i )-a-(2-Naphthyl)aminomethyl]ferrocene was prepared in three steps from ferrocenyl 2-naphthyl ketone featuring an asymmetric CBS reduction with >99% ee (eq 1). After protection of the secondary hydroxyl group with an acetyl group, a nucleophilic displacement of the acetoxy group with an amino group proceeded with retention of stereochemistry. A range of different variations of [(i )-a-(2-naphthyl)aminomethyl]ferro-cene could be prepared using this sequence with similar efficiency. 

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