A facile synthesis of the spiroindoline-based growth hormone secretagogue, MK-677

Abstract A facile and improved route for the synthesis of the orally active spiroindoline-based growth hormone secretagogue, MK-677 was described. The key step adopted the Fischer indole/reduction strategy. The preparation of the key intermediates N -protected piperidine carboxaldehyde 5 and the N -Boc- O -benzyl- d -serine ( 2 ) are also optimized.