Catalysts and Related Processes For Producing Optically Pure Beta-Lactones From Aldehydes and Compositions Produced Thereby
AssigneeThe University of Toledo
InventorYun-Ming Lin
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Abstract
Bi-functional cobalt-containing catalysts useful for making stereospecific compounds and compositions, along with methods of making, and uses thereof in the syntheses of optically pure β-lactones from aldehydes and ketene are described. Precursors, intermediates, compositions, and particular features of the use if the compositions, such as high enantiomeric selectivity, high yield and low mole percent of catalyst useful are provided.
Claims16
A method for making a β-lactone (12), represented by Scheme 4:
- wherein:
- the aldehyde (11) is selected from:
- aromatic aldehydes and aliphatic aldehydes;
- the β-lactone (12) has an enantiomeric excess (ee) greater than or equal to about 70%;
- and
- R represents, independently for each occurrence:
- H, alkyl, or aryl.
A process of enantioselectively producing a β-lactone compound, the process comprising:
- enantioselectively converting ketene into an ammonium enolate using a Lewis acid-Lewis base bi-functional catalyst, and
- delivering the ammonium enolate into an aldehyde in the presence of the bi-functional catalyst under conditions sufficient to produce a β-lactone compound;
- wherein the enantioselective conversion of the aldehyde produces the β-lactone compound in an enantiomeric excess (ee) of at least about 90%.
A method for making a substantially optically pure hydroxamate aldol represented by the Scheme 6:
- wherein R is selected from:
- BnOCH2CH2—;
- BnOCH2—;
- CH3(CH2)4CH2—;
- CH3(CH2)9CH2—;
- PhCH2CH2—;
- PhCH2—;
- 2-chlorophenyl-;
- 2-fluorophenyl-;
- 3-chlorophenyl-;
- 3-fluorophenyl-;
- 4-nitrophenyl-;
- or, 4-cyanophenyl-;
- and
- wherein the hydroxamate aldol has a yield of at least 95% and an enantiomeric excess (ee) greater than about 98%.
A compound of the Formula I
- wherein:
- one of X1 through X4 is alkoxy, alkyl, or a linker, and the remaining three are hydrogen;
- Y is alkyl, alkenyl, or alkynyl;
- and
- R1 through R4 are alkyl (C3-10) or silyl.
A stereoisomer selected from the group consisting of compounds 10A1, 10A2, 11A1, 11A2, 12A1, 12A2, 13A1, and 13A2:
- wherein:
- Y is alkyl, alkenyl, or alkynyl;
- and
- each R is alkyl (C3-10) or silyl.
A method of conducting an enantioselective [2+2] cycloaddition reaction between an aldehyde and an unsubstituted ketene, the method comprising using a catalyst of compound (10):
Dependencies are inferred from the claim text.