Patent ID: 11884613
Assignee: CHIROGATE INTERNATIONAL INC.
Field: Organic fine chemistry (Chemistry)
Classification: CPC C | IPC C

Claim 3:
4. The process according to claim 1 for preparing a compound of Formula 4a,, wherein Y is —CH2OP or —COOR1; P is H or a hydroxyl protective group; and R1 is C1-7-alkyl, aryl or aralkyl, each of which is unsubstituted or substituted by C1-4-alkyl, C2-7-alkenyl, C2-7-alkynyl, nitro, halogen or alkoxy, the process comprising the steps of:
(1′) reacting an optically enriched compound of Formula (R)-1:, wherein X is F, Cl, Br, I, or —OTs; P1 is a hydroxyl protective group; and Y is as defined above, with a cuprate derived from a compound of Formula L1a, Formula L2a, or Formula L3a:, wherein X1 is Cl, Br, or I; and P2 is a hydroxyl protective group, to form a compound of Formula 2a:, wherein P, X, and Y are as defined above;

(2′)methylenation of a ketone radical of the compound of Formula 2a to form a compound of Formula 3a:, wherein P, X and Y are as defined above;

(3′) performing an intramolecular cyclization reaction to the compound of Formula 3a to form the compound of Formula 4a:, wherein P and Y are as defined above; and

(4′)optionally performing a deprotecting reaction for removing P1 and/or P2.