Stereoselective Reactions. XXII. Design and Synthesis of Chiral Chelated Lithium Amides for Enantioselective Reactions.

Practical One-Step Synthesis of Koga's Chiral Bases

“…In general, the two types of chiral bases give similar enantioselectivity in ketone deprotonations but amine (R,R)-1 is the more popular as it is easy to prepare and commerically available; there is a reluctance to use Koga's bases presumably because of the length and difficulty of their synthesis. 5 Although difficult to access, Koga's chiral bases have been used to prepare intermediates for the total synthesis of penitrem B, reiswigin A and a range of indolizidine and tropinone alkaloids. 6 In an attempt to increase the popularity of Koga's bases, we now report that (R)-styrene oxide 7 can be converted into diamines (R)-2-4 via a simple and efficient one-pot process.…”

Synthesis of polymer-supported chiral lithium amide bases and application in asymmetric deprotonation of prochiral cyclic ketones

“…Two other functional groups we incorporated into our polymer-supported CLAB's were diamines synthesized via a modification of Koga's procedure. 24,25 They were attached to the polymer through the nitrogen atom. The resulting polymer-supported diamines 2a and 2b are also shown in Scheme 1.…”

Approaches to Catalytic Asymmetric Formation and Reactions of Lithium Enolates.

“…Conversion of a carbonyl compound (1) to an enolate anion (2) by deprotonation, and the reaction of 2 with an electrophile to give the corresponding a-substituted carbonyl compound (3) constitute the fundamental and widely used processes in synthetic organic chemistry. In the last ten years, we have been studying the possibility of making these processes enantioselective through the agency of chiral chelated lithium amides or their corresponding amines.…”