1-Substituted β-Carbolines by a Pictet−Spengler Cyclization with Thioortho Esters and Carbon−Carbon Bond Formation via N-Sulfonyl Iminium Ions Generated from N,S-Sulfonyl Acetals
摘要:
[GRAPHICS]The reaction of N-tosyltryptamines with thioortho esters, leading to 1-thiosubstituted tetrahydro-beta-carbolines under modified Pictet-Spengler conditions, is described. The 1-heterosubstituted beta-carbolines furnished 1-substituted beta-carbolines upon reaction with Grignard reagents and silyl derivatives under Lewis acid promotion.
Herein, we report a biomimeticoxidativecoupling cyclization strategy for the highly efficient functionalization of tetrahydrocarbolines (THCs). This process enables rapid access to complex isochromanoindolenine scaffolds in moderate to excellent yields. The reaction proceeds smoothly and rapidly (complete within minutes) in an open flask. This operationally simple protocol is scalable and compatible
Rhodium(I)-Catalyzed Cycloisomerization of Nitrogen-Tethered Indoles and Alkylidenecyclopropanes: Convenient Access to Polycyclic Indole Derivatives
作者:Di-Han Zhang、Xiang-Ying Tang、Yin Wei、Min Shi
DOI:10.1002/chem.201302331
日期:2013.10.4
At the end of its tether: A new synthetic protocol for the preparation of polycyclic indole derivatives has been developed from a rhodium(I)‐catalyzed cycloisomerization of a nitrogen‐tethered indole and alkylidenecyclopropane, affording the corresponding tetrahydro‐β‐carboline derivatives in moderate to good yields (see scheme). Further transformations give a direct and rapid route to tetracyclic
TCCA-mediated oxidative rearrangement of tetrahydro-β-carbolines: facile access to spirooxindoles and the total synthesis of (±)-coerulescine and (±)-horsfiline
作者:Manda Sathish、Akash P. Sakla、Fabiane M. Nachtigall、Leonardo S. Santos、Nagula Shankaraiah
DOI:10.1039/d1ra02381k
日期:——
Multi-reactive centered reagents are beneficial in chemical synthesis due to their advantage of minimal material utilization and formation of less by-products. Trichloroisocyanuric acid (TCCA), a reagent with three reactive centers, was employed in the synthesis of spirooxindoles through the oxidative rearrangement of various N-protected tetrahydro-β-carbolines. In this protocol, low equivalents of
We describe iron‐catalyzed oxidativecouplingcyclization of tetrahydrocarbazoles or THβCs or THγCs to form benzofuroindolenines as fused polycyclic indoles. This mild, efficient and simple approach afforded a library of more than 52 complex compounds across a range of substrate classes with good to excellent yields.