Abstract
(E)‐[4‐13C]‐3‐Methylcrotonic acid was converted to [4‐13C]‐3‐methyl‐2,3‐epoxybutyric acid, which was treated with ammonia to yield a mixture of [4‐13C]‐β‐hydroxyvaline and [4‐13C]‐β‐amino‐α‐hydroxyisovaleric acid, from which the β‐hydroxyvaline of known chirality at C‐3 relative to C‐2 was isolated. Similarly, (E)‐[4,4,4‐2H3]‐3‐methylcrotonic acid was converted via the epoxide, into a mixture of [4,4,4‐2H3]‐β‐hydroxyvaline and [4,4,42H3]‐β‐amino‐α‐hydroxyisovaleric acid, from which the β‐hydroxyvaline was isolated.