CHIRAL SYNTHESIS VIA ORGANOBORANES .40. SELECTIVE REDUCTIONS .55. A SIMPLE ONE-POT SYNTHESIS OF THE ENANTIOMERS OF (TRIFLUOROMETHYL)OXIRANE - A GENERAL-SYNTHESIS IN HIGH OPTICAL PURITIES OF ALPHA-TRIFLUOROMETHYL SECONDARY ALCOHOLS VIA THE RING-CLEAVAGE REACTIONS OF THE EPOXIDE

An extremely efficient one-pot asymmetric synthesis of either enantiomer of (trifluoramethyl)oxirane (3,3,3-trifluoro-1,2-epoxypropane, 4) in 64% yield and 96% ee has been achieved via the asymmetric reduction of the commercially available 1-bromo-3,3,3-trifluoro-2-propanone with either (+)- or (-)-...

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Bibliographic Details
Published inJournal of organic chemistry Vol. 60; no. 1; pp. 41 - 46
Main Authors RAMACHANDRAN, PV, GONG, BQ, BROWN, HC
Format Journal Article
LanguageEnglish
Published WASHINGTON Amer Chemical Soc 13.01.1995
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
CATALYTIC ENANTIOSELECTIVE ADDITION
KETONES
OXIDE
ACID
DIETHYLZINC
ASYMMETRIC REDUCTION
ALDEHYDES
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Summary:An extremely efficient one-pot asymmetric synthesis of either enantiomer of (trifluoramethyl)oxirane (3,3,3-trifluoro-1,2-epoxypropane, 4) in 64% yield and 96% ee has been achieved via the asymmetric reduction of the commercially available 1-bromo-3,3,3-trifluoro-2-propanone with either (+)- or (-)-B-chlorodiisopinocampheylborane (Aldrich: DIP-Chloride), followed by ring closure of the intermediate chloroborinate, IpcBCl[OCH(CH2Br)CF3]. The ring cleavage reactions of 4 provide a general synthesis of chiral trifluoromethyl carbinols without loss of optical activity. Thus we have synthesized 1-amino-3,3,3-trifluoro-2-propanol, 1-azido-3,3,3-trifluoro-2-propanol, 1-(diethylamino)3,3,3-trifluoro-2-propanol, 1-cyano-3,3,3-trifluoro-2-propanol, 1,1,1-trifluoro-2-propanol, 1,1,1-trifluoro-2-octanol, 1-phenyl-3,3,3-trifluoro-2-propanol, 1-ethoxy-3,3,3-trifluoro-2-propanol, and 1,2-dihydroxy-3,3,3-trifluorapropane, in 61-88% yields and in 96% ee by the cleavage of 4 with the appropriate nucleophile.
ISSN:0022-3263
DOI:10.1021/jo00106a012