Dimethylmalonyl dichloride

Evans and co-workers synthesized bu-box 3 starting from commercially available (5)-ferf-leucine." Lithium aluminum hydride reduction of (iS)-tcrt-leucine afforded the amino alcohol 23 which, as shown in Figure 9.6, was acylated with dimethylmalonyl dichloride 24 to provide the corresponding bis(amidodiol) 25 in... 

Corey and Ishihara s synthesis of phe-box ligand 29 began with the trifluoro-acetyl derivative of (5)-phenylglycine 26. Treatment of 26 with methylmagnesium iodide, as shown in Figure 9.7, followed by potassium hydroxide in methanol afforded amino alcohol 27 in 88% yield (2 steps).This was then acylated with dimethylmalonyl dichloride 24 and triethylamine followed by cyclization using methanesulfonic acid at reflux to afford phe-box ligand 29 in 78% yield. 

Highly efficient catalytic asymmetric cyclopropanation can be effected with copper catalysts complexed with ligands of type 2.3 These bis(oxazolines) are prepared by reaction of dimethylmalonyl dichloride with an a-amino alcohol. As in the case of ligands of type 1, particularly high stereoselectivity obtains when R is /-butyl. Cyclopropanation of styrene with ethyl diazoacetate catalyzed by copper complexed with... 

Preparative Methods several methods for the synthesis of this ligand have been reported. The preparation usually starts with the reduction of commercially available (iS)-terf-leucine to the corresponding amino alcohol, followed by acylation with 0.5 equiv of dimethylmalonyl dichloride. The resulting dihydroxy malonodiamide is cyclized via the bis(alkyl chloride) or via the bis(tosylate) as described in an improved procedure (eq 1). ... 

Synthesis. Synthesis was accomplished as shown in Schemes 1 and 2. Reduction of the nitrobenzene with zinc/ammonium chloride gave the corresponding hydroxylamine 2. Due to the difficulty in purification, the crude reduction product was used in the reaction with dimethylmalonyl dichloride. This procedure was satisfactory in that yields of 50 to 80% of the dione 3 could be obtained. 

A series of macrocycles containing two sulfur and two nitrogen atoms was prepared in yields of 37-64% from the appropriate diacid dichlorides and diamines (method Z-5) (Siegfried and Kaden, 1984). The cyclic diamides were reduced by borane in yields of 34-64%. The reaction of dimethylmalonyl... 

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See also in sourсe #XX -- [ ]

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