Facile access to diverse all-carbon quaternary center containing spirobicycles by exploring a tandem Castro-Stephens
Ye Zhang1, Tian-Lu Zheng1, Fu Cheng1
1State Key Laboratory of Applied Organic Chemistry, School of Pharmacy, Lanzhou University Lanzhou 730000 P. R. China tuyq@lzu.edu.cn wangshh@lzu.edu.cn.
Abstract:
Efficient combination of two or more reactions into a practically useful purification free sequence is of great significance for the achievement of structural complexity and diversity, and an important approach for the development of new synthetic strategies that are industrially step-economic and environmentally friendly. In this work, a facile and efficient method for the construction of highly functionalized spirocyclo[4.5]decane derivatives containing a synthetically challenging quaternary carbon center has been successfully developed through the realization of a tandem Castro-Stephens coupling/1,3-acyloxy shift/cyclization/semipinacol rearrangement sequence. Thus a series of multi-substituted spirocyclo[4.5]decane and functionalized cyclohexane skeletons with a phenyl-substituted quaternary carbon center have been constructed using this method as illustrated by 24 examples in moderate to good yields. The major advantages of this method over the known strategies are better transformation efficiency (four consecutive transformations in one tandem reaction), product complexity and diversity. As a support of its potential application, a quick construction of the key tetracyclic diterpene skeleton of waihoensene has been achieved.
Related Concept Videos
Cycloaddition Reactions: Overview
Pericyclic Reactions: Introduction
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic...
Preparation of Diols and Pinacol Rearrangement
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction


![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)