Alanes asymmetric synthesis

Lynn Power was born in Co. Wexford, Ireland. She completed a B.Sc. degree at the National University of Ireland, Maynooth in 2004, including a final year research project with Dr. Frances Heaney. She was the recipient of the Kathleen Lonsdale Prize for the best student graduating in chemistry. She then carried out Ph.D. work at the University of St. Andrews in the area of asymmetric synthesis using chiral dioxolanones under the supervision of Dr. Alan Aitken. 

Asymmetric synthesis of pyrrolidines and pyrrolinones. This chiral -hydroxy-amine (1) reacts with a y-keto acid in refluxing toluene to form a chiral bicyclic lactam 2 in 75-98% yield. Treatment of 2 with excess alane, generated from AlCly and LiAlH4,... 

Hydroaluminadon. A stereoselective approach to cycloheptenols is based on the cleavage of 8-oxabicyclo[3.2.1]oct-6-enes. The lack of generality for the fragmentation protocol plagued the method. Now a useful procedure consists of Nilcodl -catalyzed hydroalumination and treatment of the alane with i-BUjAlCl. This method is also appropriate for the asymmetric synthesis of cyclohexenols. 

Scheme 9 Asymmetric synthesis of (S)-tiemoniimi iodide via 2-thienyl addition. Conditions 2.0 eqniv. Ti(OiPr)4, 10 mol% 44, 1.7 equiv. alane, toluene, 0 °C, 24 h...

The synthesis of 188 from epoxide 189 was done as shown in Scheme 25. Epoxide opening with a propargyl alane reagent [124], protection-deprotection of the alcohol functions, and Redal reduction led to the -allylic alcohol 194, also obtained by another route [116]. Asymmetric epoxidation-Redal epoxide opening [60-62] followed by silylation and debenzylation led to intermediate triol 195. Selective six-membered acetal formation and primary alcohol oxidation then furnished building block 188. 

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