Harold Ramis Dan Aykroyd on the screenplay for "Ghostbusters", which became one of the biggest comedy hits of all time, in which he also starred as Dr. Egon Spengler, a role he reprised for the 1989 sequel, "Ghostbusters II" (which he also co-wrote with Aykroyd). His later film "Groundhog Day" has been called his "masterpiece". His films have been noted for attacking "the smugness of institutional life ... with an impish good [will] that is unmistakably American". They are also noted for "Ramis's signature tongue-in-cheek pep talks". Sloppiness and improv were also important aspects of his work. Ramis frequently depicted the qualities
Pictet–Spengler reaction is created. Several substrate- or auxiliary-controlled diastereoselective Pictet–Spengler reactions have been developed. Additionally, List "et al." have published a chiral Brønsted acid that catalyzes asymmetric Pictet–Spengler reactions. Tryptophans: diastereocontrolled reaction The reaction of enantiopure tryptophan or its short-chain alkylesters leads to 1,2,3,4-tetrahydro-"β"-carbolines in which a new chiral center at C-1 adopts either a "cis" or "trans" configuration towards the C-3 carboxyl group. The "cis" conduction is kinetically controlled, i.e. it is performed at lower temperatures. At higher temperatures the reaction becomes reversible and usually favours racemisation. 1,3-"trans" dominated products can be obtained with "N"-benzylated tryptophans, which are accessible by reductive