Patent ID: 9701601
Date: 2017-07-11
CPC Classifications: C07B,C07C,C07D

Claim:
1. A method for synthesizing an axially chiral α-allenic alcohol having the following structural formula: wherein R wherein PG is a silyl group; said reaction is performed in an organic solvent and at a temperature of 100-130° C., in the presence of a zinc salt, and using (3) or an enantiomer thereof as a chiral secondary amine; wherein the substituted-propargyl alcohol protected by silyl group (1) and the aldehyde (2) are reacted for 5-15 hours; followed by passing the protected product through a silica-gel chromatographic column to obtain a crude reaction product; and then removing the silyl protective group by treatment with tetra-n-butylammonium fluoride, to obtain the axially chiral α-allenic alcohol product (4); wherein the molar ratio of the substituted-propargyl alcohol protected with the silyl group (1): the aldehyde (2): the chiral secondary amine (3): the zinc salt is 1-3:1-3:1:0.5-1.5; wherein said silyl group is a trimethylsilyl, triisopropylsilyl, tert-butyldimethylsilyl, or tert-butyldiphenylsilyl group; said chiral secondary amine is compound 3(a-e) having the following structural formula or an enantiomer thereof; and wherein said zinc salt is zinc chloride, zinc bromide, zinc iodide, zinc acetate, or zinc trifluoromethanesulfonate.