Domino Rh-catalyzed hydroformylation–double cyclization of o-amino cinnamyl derivatives: applications to the formal total syntheses of physostigmine and physovenine
Decarboxylative [4+2] Cycloaddition by Synergistic Palladium and Organocatalysis
作者:Lars A. Leth、Florian Glaus、Marta Meazza、Liang Fu、Mathias K. Thøgersen、Emma A. Bitsch、Karl Anker Jørgensen
DOI:10.1002/anie.201607788
日期:2016.12.5
based on synergisticcatalysis, combining palladium‐ and organocatalysis has been developed. The palladium catalyst activates vinyl benzoxazinanones via a decarboxylation to undergo a [4+2] cycloaddition with iminium‐ion activated α,β‐unsaturated aldehydes. The reaction is demonstrated to proceed for a number of combinations of vinyl benzoxazinanones reacting with α,β‐unsaturated aldehydes, providing
Coupling cyclizations with fragmentations for the preparation of heteroaromatics: quinolines from o-alkenyl arylisocyanides and boronic acids
作者:Christopher J. Evoniuk、Michelle Ly、Igor V. Alabugin
DOI:10.1039/c5cc04391c
日期:——
Stereoelectronic restrictions on homoallylic ring expansion in alkyne cascades can be overcome by using alkenes as synthetic equivalents of alkynes in reaction cascades that are terminated by C-C bond fragmentation....
Domino Rh-catalyzed hydroformylation–double cyclization of o-amino cinnamyl derivatives: applications to the formal total syntheses of physostigmine and physovenine
A parallel, versatile and efficient route to synthesis of pyrrolidinoindoline and tetrahydrofuranoindoline alkaloids from cinnamyl derivatives has been developed, featuring a domino Rh-catalyzed hydroformylationâdouble cyclization sequence. This method can be applied to the syntheses of anti-Alzheimer drugs such as physostigmine and physovenine.
The new cyclic carbodiimides 3 are synthetized from bis(iminophosphoranes) 2 and Boc2O in the presence of DMAP; similar results can be achieved from the N-Boc-protected bis(iminophosphoranes) and carbon dioxide.