(+)-Biotin 1 has received considerable attention as an important vitamin for human nutrition and animal health. 1 Since the first total synthesis of (+)-biotin was accomplished about 50 years ago, a number of synthetic methods have been developed. 2 Among them, a method utilizing thiolactone 2 as a key intermediate has been one of the most reliable approaches so far developed. 3 The method is, however, not entirely satisfactory because a number of steps ...
