In this paper, we show that the quantum Stokes matrices, of certain meromorphic linear system of ordinary differential equations, give rise to a family of Drinfeld isomorphisms from quantum groups to the undeformed universal enveloping algebra of gl(n). In particular, we compute explicitly the Drinfeld isomorphisms corresponding to caterpillar points on the parameter space. Our computation unveils a relation between the asymptotics of confluent hypergeometric functions and the Gelfand-Zeitlin subalgebras.As by products, we show that the Drinfeld isomorphisms at caterpillar points coincide with the Appel-Gautam isomorphisms. Then by going to the semiclassical limit, we place the results in this paper into the context of Poisson geometry. As an application, we prove the conjecture of Appel and Gautam, i.e., their isomorphisms are canonical quantization of the Alekseev-Meinrenken diffeomorphisms arising from the linearization problem in Poisson geometry.