An Enantioselective Total Synthesis of (+)-Geissoschizine
作者:Stephen F. Martin、Kevin X. Chen、C. Todd Eary
DOI:10.1021/ol990554a
日期:1999.7.1
[formula: see text] A concise asymmetric synthesis of the indole alkaloid (+)-geissoschizine (1) has been completed. The synthesis features the highly diastereoselective vinylogous Mannich reaction of 3 with 4 to give 5, which is elaborated into the key tetracyclic intermediate 7 in two steps. Following the stereoselective introduction of the ethylidene moiety to give 9, reduction of the lactam and
A neworganocatalyticstrategy for the synthesis of enantioenriched aza‐Baylis–Hillman type products via a frustrated vinylogous reaction is presented. This process proceeds under mild conditions with good yields, completed Z/E selectivity and excellent enantioselectivities. Moreover, easy derivatizations of the final products led to important building blocks of organic synthesis such as 1,3‐aminoalcohols
Disulfonimide-Catalyzed Asymmetric Vinylogous and Bisvinylogous Mukaiyama Aldol Reactions
作者:Lars Ratjen、Pilar García-García、Frank Lay、Michael Edmund Beck、Benjamin List
DOI:10.1002/anie.201005954
日期:2011.1.17
talk about six! A new chiral disulfonimide catalyzed vinylogous Mukaiyamaaldol addition of crotonic acid derived nucleophiles to aldehydes has been developed and the concept of vinylogy was further expanded to double vinylogous, sorbic acid derived nucleophiles. This reaction is an example of a previously unknown ε‐selective bisvinylogous MukaiyamaAldol addition that extends the substrate by six
A One-Pot Non-Aldol-Aldol Vinylogous Mukaiyama Aldol Tandem Sequence for the Rapid Construction of Polyketide Frameworks
作者:Markus Kalesse、Nicola Rahn
DOI:10.1055/s-2005-863743
日期:——
The rapid assembly of polyketide segments remains one central task in the field of natural product synthesis. Besides the stereoselective assembly of carbon frameworks functional group transformations and protecting group manipulations have to be optimized in order to streamline organic synthesis. The activated aldehyde derived from Jung’s non aldol-aldol method serves as an intermediate for the subsequent vinylogous Mukaiyama aldol reaction.
Vinylogous Mukaiyama aldol reactions with triarylboranes
作者:Mathias Christmann、Markus Kalesse
DOI:10.1016/s0040-4039(00)02254-1
日期:2001.2
The first vinylogousMukaiyamaaldolreactions with tris(pentafluorophenyl)borane and triphenylborane are described. Both Lewis acids diastereoselectively generate the C19–C21 all-syn stereo triad of ratjadone, and in the case of tris(pentafluorophenyl)borane the reaction proceeds with substoichiometric amounts.