An N-propargyl pyrroloimidazolone with syn stereochemistry derived from L-proline serves as a starting material for the diastereoselective synthesis (> 95:5 dr) of propargyl alkynes or allenamides by direct quench of its lithiated intermediate with alkylating agents or aldehydes/ketones, respectively. Use of the epimeric anti pyrroloimidazolone starting material results in reversal of stereochemistry at the propargyl position in the products, without the need to prepare a separate substrate from D-proline. Lithiation of the syn pyrroloimidazolone and quench with prochiral benzaldehydes without prior transmetalation gives allenamides with crystallographically verified atypical stereochemistry of the benzylic alcohol in > 95:5 dr. The epimeric series of benzylic alcohols may also be obtained in > 95:5 dr by employing transmetalation with chlorotitanium triisopropoxide prior to aldehyde quench. Density Functional Theory (DFT) computational studies provide a rationale for the change in benzylic alcohol stereochemistry by virtue of differing stereofacial attack in 6,5-bicyclic (Li) or 6-membered (Ti) transition states.

We describe in this paper thethermal decomposition in air of several complexes of palladium(lI) chloride with imidazole and N-methylimidazole. Although the final process of the decomposition gives (PdCI~) n which 'then decomposes to pa ladium which oxidizes to PdO, there are interesting differences in the initial decomposition path. The reasons for these differences appear to be related to the trans-effect and to the presence in the imidazole complexes of .hydrogen bonds which break down at temperatures of around 220 ~ . This paper is the first of a series dedicated to the study of several complexes of palladium(II) chloride with imidazole and N-substituted imidazole. We describe here the thermal decomposition of some of this complexes in air. No attempt was made to obtain kinetic data, our main interest being to determine the existence of new species formed during the process of decomposition. Although the thermal decomposition of palladium complexes is a fertile area of study [1 ], there are, to our knowledge, no previous reports of the thermal behaviour of palladium imidazole complexes. The only example refering to complexes of this kind with elements of the nickel group refer to nickel(II) complexes [2] which, as expected from the general trends in the chemistry of nickel, palladium and platinum [3], differ considerably from those studied here. ExperimentalAll the complexes were obtained as described in reference [7]. The thermoanalytical curves were obtained on a Mettler 181 thermoanalyser. Samples of ,-, 10 mg were placed on uncovered platinum crucibles located on top of the thermocouple. The heating rate was standarized at 10~

Background Laparoscopic technical surgical skills (LTS) are considered a fundamental competence for General Surgery residents. Several simulation tools (ST) have been explored to develop LTS. Although a plethora of systematic reviews evaluate the translation of LTS developed in simulation to real surgery, there is a lack of evidence that clarifies effectiveness of different validated ST in acquisition of LTS in surgical residents. The aim of this systematic review (SR) is to summarize published evidence on ST validation used for surgery education and training. Methods A protocol was published in PROSPERO. A SR was carried out following PRISMA guidelines. Complete published articles in English or Spanish that validate either content or construct, plus another form of validation of ST to acquire LTS in general surgery were included. Articles that used only one validation or did not validate an ST were excluded. Results 1052 publications were initially identified across all searched databases. Title review identified 204 studies eligible for full text screening. 10 studies were included for final review. Two studies assessed both face and content, 4 face and construct, and 4 face, content and construct validity. None of the studies presented comparable outcomes due to metrics variation and scores used for the validation strategies. Conclusions This study assessed validated laparoscopic simulation models, particularly in content and construct validity. Articles reported an increased use of simulation models in laparoscopic training with positive feedback from trainees, but few studies reported validation of training model. Validation strategies are not standardized, limiting comparability between them.

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Background: Laparoscopic technical surgical skills (LTS) are considered a fundamental competence for General Surgery residents. Several simulation tools (ST) have been explored to develop these skills. Although a plethora of systematic reviews evaluate the translation of LTS developed in simulation to real surgery, there is a lack of evidence that clarifies effectiveness of different validated ST in acquisition of LTS in surgical residents. The aim of this systematic review (SR) is to summarize current published evidence on ST validation used for general surgery education and training.Methods: An initial protocol was published in PROSPERO, under registration number: CRD42020205397. A SR of the literature was carried out following PRISMA guidelines. Complete published articles in English or Spanish that validate either content or construct, plus another form of validation of ST to acquire LTS in general surgery were included. Articles that used only one validation strategy or did not validate an ST were excluded.Results: 1052 publications were initially identified across all searched databases. Title review identified 204 studies which were eligible for full text screening. 10 studies were included for final review. Two studies assessed both face and content, four face and construct, and four face, content and construct validity. None of the studies presented comparable outcomes due to metrics variation and scores used for the validation strategies.Conclusions: This study assessed validated laparoscopic simulation models, with particular interest in content and construct validity. Articles reported an increased use of simulation models in laparoscopic training with positive feedback from trainees, but few studies reported validation of training model. Validation strategies are not standardized, limiting comparability between them.