Synthesis of Reserpine by Robert B. Woodward (1956)
All 5 total syntheses to date have used a Diels–Alder reaction to form the molecule's fused bicyclo[2.2.2]octane ring system. The reaction has also featured prominently in approaches by Baran, Trauner, Nicolaou, Chen, Movin, Sorensen and others.[2]
9: Strategies in Reserpine Synthesis - Chemistry …

Woodward’s group reported the first synthesis of Reserpine in 1956 (J
Interestingly, despite the hugely varied interests and specializations of the groups involved, all five of the successful total syntheses reported to date have constructed the molecule’s prominent bicyclo[2.2.2]octane ring system using the venerable Diels–Alder reaction (often in conjunction with the similarly tried-and-true tactic of oxidative dearomatization to establish the diene). That said, the number of Diels–Alder variants employed is impressive, and you could almost imagine giving a short lecture course on the reaction using nothing but examples from synthetic studies on maoecrystal V. I’ve tried to illustrate the variety below.
The Stork Synthesis of (-)-Reserpine - Organic chemistry
From the outset of this campaign, Woodward was said to have regarded the synthesis of reserpine as a problem in stereochemistry, and here is a near-perfect solution that establishes, in just four steps, all five contiguous sterocentres around the E-ring. Despite some rather low yields, tens of grams of the required tetracyclic intermediate could still be obtained using this chemistry.

Reserpine synthesis pdf | qunhzeq | Flickr
and (2000)A formal synthesis of reserpine: hydrindane approach to the Woodward’s ring-E precursor. In: Journal of Chemical Society: Perkin Transactions 1 . pp. 1399-1404.