152397-94-9Relevant academic research and scientific papers
Highly enantioselective Mukaiyama aldol reaction of αα-dichloro ketene silyl acetal: An efficient synthesis of a key intermediate for diltiazem
Imashiro, Ritsuo,Kuroda, Tooru
, p. 974 - 979 (2003)
An efficient synthesis of methyl (2R,3S)-3-(4-methoxyphenyl)glycidate (-)-2, a key intermediate for diltiazem (1), has been developed on the basis of the highly enantioselective Mukaiyama aldol reaction of p-anisaldehyde (4a) with αα-dichloro ketene silyl acetal 5. Thus, the reaction using a stoichiometric amount of chiral oxazaborolidinone catalyst 12a proceeded to excellent yield (83%) and high enantioselectivity (96% ee), together with the chiral ligand 13a in nearly quantitative recovery. The reaction using a substoichiometric amount of 12e (20 mol%) also proceeded to excellent yield (88%), with somewhat lower enantioselectivity (77% ee). The aldol product 3a thus obtained was easily converted to (-)-2 in excellent yield (80%) and high optical purity (>99% ee). The highly enantioselective Mukaiyama aldol reaction with 5 catalyzed by 12a proved to be applicable to various aldehydes. An efficient preparation of 5 from inexpensive starting materials was also described.
Asymmetric synthesis of methyl (2R,3S)-3-(4-methoxyphenyl) glycidate, a key intermediate of diltiazem, via Mukaiyama aldol reaction
Imashiro, Ritsuo,Kuroda, Tooru
, p. 1313 - 1315 (2007/10/03)
Methyl (2R,3S)-3-(4-methoxyphenyl) glycidate, a key intermediate of diltiazem, was synthesized in good yield with high enantioselectivity based on chiral oxazaborolidine-mediated Mukaiyama aldol reaction of p-anisaldehyde with α,α-dichloro silyl ketene acetal (up to 96% ee), followed by reduction and cyclization.
Asymmetric reduction of aromatic ketones. II. An enantioselective synthesis of methyl (2R,3S)-3-(4-methoxyphenyl)glycidate
Matsuki,Sobukawa,Kawai,Inoue,Takeda
, p. 643 - 648 (2007/10/02)
Asymmetric reduction of some 3-keto esters (6, 8, and 11) to 3-hydroxy esters (7, 9, and 12) with various chiral reducing agents was investigated. The products (9 and 12) were converted to methyl (2R,3S)-3-(4-methoxyphenyl)glycidate (2R,3S-3), a key intermediate in the practical enantioselective synthesis of diltiazem (1).
