This is the only place I've seen it, in smaller amounts. Maybe you can email them about larger amounts.
https://www2.acadia.net/cgi-bin/BAC/web_store.cgi
NEW! LIPOIC ACID, R ALPHA-, 99.7+% Due to numerous requests and lower prices we offer this natural form of Lipoic Acid that has been used in much recent research. Some writers claim R-Lipoic Acid may be 10 times more effective in mitochondrial ATP production than the normal 50:50 mix of R and S forms found in regular Lipoic Acid (I have not seen hard evidence of this). Search “R-lipoic acid” on the web. In capsules, R-Lipoic Acid is being offered with SRPs from $25 for 3 grams to $27 for 9 grams. There is speculation that caps may be less effective than powder due to heating that may occur during the commercial encapsulation process. C of A and 3rd party analysis available. Store cool, dry, out of direct sunlight. May not ship well in hot weather. 20 grams powder (200 X 100mg doses!). $18.75. Code 508.6