Work

Asymmetric Traceless Petasis Borono‐Mannich Reactions of Enals: Reductive Transposition of Allylic Diazenes

Year: 2017

Type: article

Abstract: The traceless Petasis borono-Mannich reaction of enals, sulfonylhydrazines, and allylboronates, catalyzed by chiral biphenols, results in an asymmetric reductive transposition of the in situ generated allylic diazene. Acyclic 1,4-diene products bearing either alkyl- or aryl-substituted benzylic stereocenters are afforded in excellent yields and enantiomeric ratios of up to 99:1. The use of crotylboronates in the reaction results in concomitant formation of two stereocenters in either a 1,4-syn or anti relationship from the corresponding E- or Z-crotylboronate used in the reaction. The use of β-monosubstituted enals in the asymmetric traceless Petasis borono-Mannich reaction of crotylboronates installs tertiary methyl-bearing stereocenters in good yields and high enantioselectivities.

Source: Angewandte Chemie International Edition

DOI: 10.1002/anie.201708784

Authors: Yao Jiang, Regan J. Thomson, Scott E. Schaus

Institutions: Boston University, Northwestern University

Language: English

Topic: Asymmetric Synthesis and Catalysis

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, National Institute of General Medical Sciences

Awards: Structural and Sterochemically Diverse Heterocycles for the Small Molecule Reposi, Enantioselective Catalytic Boronate Reactions, New Stereoselective Fragment Coupling Reactions for Organic Synthesis